GCSE AQA Biology Paper 1 2023 Higher Walkthrough

Hey guys, welcome back to another science video. This time once again, we're going through all of the GCSE science papers starting with combined, then moving on to triple afterwards. I'm also open to comments suggesting if you want me to go through a topic in particular, but I do try and teach at least a little bit during these videos as well. So, I don't just kind of give you the mark scheme because that's kind of pointless. But yeah, without further ado, let's get into it with bio paper 1 2023. First question, it says, communicable non-communicable diseases are major causes of ill health. Which disease is a non-communicable disease? So communicable means that you can spread it. So you can catch it from another person. So something like the common cold, flu. So if we look through here, you can catch gorrhea and AIDS from other people. Now malaria also spreads through protest. So things like mosquitoes. So cancer is the only thing you can't catch. You can't catch cancer from from anything else. Moving on. So obesity is a risk factor for many non-communicable diseases. Give one non-communicable disease that obesity is a risk factor for do not refer to the disease given in part one. So you can't just say cancer again. Um something like diabetes would be I was going to say a good one. It's not a good one but you can also say coronary heart disease because again you can't catch that. That's something that's developed in your itself or heart disease something along those lines. National policies are used to help people who are obese to lose weight. One national policy is to reduce the amount of sugar added to food and drink. suggest one other national policy that can be used to help people lose weight. Well, we live in the UK, so you might be aware that a few years ago they put in a sugar tax, which again encourages people to drink and eat things with less sugar in them. But you can also have uh education. So just education in schools about the dangers of eating uh sugar or high fat foods, high calorie foods, whatever you want to call it. You can have government advertising. You can also have restrictions on advertising. So, for example, with uh cigarettes, you may have noticed that you've never seen an advert for cigarettes because it's illegal to advertise cigarettes in the UK. And also on the packaging itself, it has to have those disgusting images of like black lungs and stuff like that. So, it's another one. Um, calorie information on takeaways and things like that and on on restaurant menus. If you travel around the world, not every country has that. That's something you Well, it's not unique, but it's something that the UK does in particular. anything along those lines. BMI is one measure of obesity and it's calculated by taking someone's mass in kilograms, dividing it by their height squared, and then basically the bigger the BMI, the more overweight or obese you are. A person is 1.64 m tall and has a mass of 69 kilos. Determine the BMI category for the person. So again, we're just substituting into a formula. So it says you take their mass, which is 69 kilos, and you divide it by their height in me squared. It's already in meters. So divide by 1.64 squared. And we can kind of work out a value here. 69 / 1.64 to the^ 2 gives me 25.7. Let's call it which if you notice is in this region here, which means they are overweight. For three marks, I think that's actually quite nice. It's not a bad question at all. Just don't be afraid to substitute into equations. Scientists investigated the effect of smoking and of BMI on the birth mass of babies. Women's BMI categories were determined before the woman the women became pregnant. Sorry. Suggest why these categories were determined before the women became pregnant. Well, if we think about what happens when a woman gets pregnant is of course they're going to increase their body weight because they're growing a human being inside them, right? So, if that baby weighs anything, then of course it's going to add to that. But also women do undergo changes which increase their body mass anyway when they're pregnant. So simply put, women gain mass from pregnancy or actually I'm going to say gain mass during pregnancy because obviously you it won't last afterwards or at least it doesn't have to last afterwards um because of the baby, right? So logically then they give us the results between smokers and non-smokers. I would always recommend having a look at the graph first or the chart or whatever just to kind of see what the patterns are. So if you notice if you're a smoker, the number of people in each category is lower. Um at least sorry the mean never mind the mean birth mass of the baby in grams is lower consistently in all four categories. So again all four categories smokers have a lower baby mass than non-smokers. So it says here give two conclusions that can be drawn. So what I just said is one of them. Smokers have lower mean baby mass than non-smokers. And what else could we um what other conclusions? Well, is it just that it's less? Well, if you look, there's actually some kind of discrepancies, right? So for example for the underweight people it seems to have had a much bigger impact than let's say for overweight people. So you can see how the difference is different. So that's a conclusion you can draw. So you can either say it has the biggest impact for underweight women or it has the least impact for overweight women. Both of those will also give you um give you the marks. So either it had the lowest effect for overweight women because the difference is smallest or had the biggest effect for underweight women because the difference is the biggest. Any one of those two would give you the second mark. So this is specifically about measles which again you do learn about. You need do need to know some specifics about measles. And it says describe how the measel virus is transferred from person to person. So it's always through coughs and sneezes. And what happens when you cough or sneeze? Well, there are viruses. What? All right. Viruses in the droplets produced which are inhaled by other people. It's kind of disgusting, isn't it? Which, by the way, is why you need to cover your mouth when you sneeze or cough, you know, and that's also why people get really sick around kids because they don't tend to cover their mouths, which means all of that snot and those droplets just inhaled by everyone. But anyways, that's enough ranting. Athletes foot is also a communicable disease. It's caused by a fungus, which is disgusting. Um, the athletes foot fungus infects the skin on the feet. Apparently, 17% of the UK population have a athletes foot, which is disturbing. Here we have the estimated population is 67,96 sorry 67,961,900. Calculate how many people are estimated to have athletes foot. We're just taking 17% of that number. Again, use your maths knowledge. I would change that to a multiplier. So, literally just 0.17 times that big number. Also, there is on your calculator a percentage button down here. So you can literally just do 17 shift percentage sign and do that. So 67 9619 0. It's like a phone number. 11.5 million people. That's interesting. That's it. Not bad. And lastly, athletes foot fungus grows in moist conditions. Suggest one way a person could reduce their chance of c catching athletes foot. Well, first of all, if it's moist conditions, that means you want to keep it dry. So, when might your feet get wet? Well, simply put, you can dry your feet after washing or just getting wet in general, like being outside, right? Anything like that. But also, you can get um this fungicide that you can spray on your foot, which obviously kills fungus, fungus side, right? Um don't share socks with other people, things like that. Um, and also don't walk around barefoot, which is just good advice anyway because you can also get verukas, which are a different type of disease as well, which are painful and difficult to remove. Figure two shows an onion cells viewed using a light microscope. And you can kind of see the the cell structure here. Here's the apparatus given to the student. You have a microscope. You have a prepared slide of onion cells. So, you don't need to talk about how you prepare them. They're just given. And a ruler. Describe how the student could use this to estimate the mean length. Once again, you don't need to talk about preparing the onion slides because it's already done. Okay, so if you write about that, you will lose marks or at least you won't gain any marks. So, how do you do it given that um equipment? Well, first of all, you want to place the ruler on the microscope stage, right? Because you're going to use the ruler to actually measure the the length. So, you want to have it like alongside here. And you want to make sure that the um microscope is focused on the ruler itself. Okay, cool. What next? Well, what you're going to do is you're going to measure the diameter of the field of view. So again, you're not going to measure an individual cell because if you look at the shape, look how bendy and weird it is. It's going to be hard to measure the width, right? So instead, you measure from end to end how wide the field of view is. So maybe like 5 cm or something along those lines. Then what you're going to do, so then uh change the focus to the actual um cells. So now you're focusing on the cells using the same magnification and you just count the number of cells that fit across the um field of view. Cool. Then all you're going to do is you're going to divide that diameter by the number of cells. So let me give you a demonstration really quick. What you do is you measure from here to here the width. And let's say that width is 5 cm, right? For argument sake. It's going to be smaller than that, but whatever. Then all you do is you count from here to here going all the way along how many cells you have. So we have one, two, three cells and then a half. So say 3.5. And all you do is you take that diameter and you divide it by 3.5. That's the estimated cell width, right? because you've just taken the number and done it. You could technically also do it vertically as well. It won't make any difference, but anything along those lines will will work. Now, this question here, it was not answered super well, but it says circulatory system includes the heart, blood vessels, and blood. The heart pumps the blood in a double circulatory system. What is meant by this? Because some people said, "Oh, the heart pumps to the blood. pumps to the lungs, for example." You need to be a bit more specific. There are a few different things you can do, but bear in mind you need to get two marks. So, you can get one mark for saying something like um the the heart the blood travels around the heart twice before it goes around, right? So, it passes through the heart twice on each circuit. That only gives you one mark. Instead, what they're asking for is specifically what is meant by it. So, if you ask your teacher, why is it called a double circulatory system? What would they say? where they would say that one side of the heart pumps blood to the lungs and the other side of the heart pumps blood to the rest of the body. Now, we do need to be a little bit more specific. We need to say which side. So, you can say just left and right side or you can say right ventricle pumps blood to the lungs, left ventricle pumps blood around the body. Something along those lines, but you have to be very very very specific when you're talking about it. Now, heart rate is controlled by a group of cells that act as a pacemaker. Where in the heart is the pacemaker found? It is the right atrium. Cool. Which blood vessel carries deoxxygenated blood? And there's a reason why they don't just say arteries and veins because it's not just one or the other. Well, the pulmonary artery carries deoxxygenated blood. Now, it might seem weird because arteries don't, you know, when when you first learn about arteries that they carry oxygenated blood. Remember pulmonary means lungs. So this is the blood that's being pumped to the lungs to become oxygenated. Okay? Whereas the pulmonary vein carries the oxygenated blood back to the heart for it to then be pumped around the heart um using the coronary artery or the aorta. So yeah, be careful with that. So the structure of a vein is different from the structure of an artery. One difference is that veins have valves but arteries do not. But why? Well, what's the point of having a valve? It's to prevent blood flowing backwards. Yeah, that's the that's the point, right? So, why would a vein need it but not an artery? Well, what's the difference between artery and a vein? Well, an artery carries blood at a much higher pressure whereas a vein is at a much lower pressure. So, simply put, arteries don't need them because the blood is traveling at such high pressures that it doesn't it's not at risk of flowing backwards. So this is because blood in veins travels at lower pressure. Cool. Now we have to describe two structural differences between a vein and artery. Obviously except valves because they've given that one already. Well, bunch of things you could say. Lumen The lumen is basically the empty hole. You know like when you have a straw, the lumen would be the hole, right? If that makes sense. So the lumen in is um wider in veins. You can also say that um it has a thinner layer of muscle as well because again it doesn't have to withstand higher pressures or a thinner layer of elastic tissue that would also be accepted. A leaf is a plant organ. Figure four shows tissues in a leaf. So we have all these different tissues and they're labeled A, B, C, and D which means you're probably going to have to say which one's which. Which tissue is the epidermis? The epidermis is the outer layer of the of the um cell. So it's going to be tissue A for this one. Perfect. And explain how the spongy misoil is adapted for its function. So again, if we have a look at this, this is the spongy misophil. How is it adapted for its function? And obviously more importantly, what is the function in and of itself? Well, the function that we're talking about is to allow gas exchange between carbon dioxide and oxygen because they need to get rid of oxygen needs to take in carbon dioxide for photosynthesis. So, you know, how is it adapted? Well, if you notice these cells here and these cells here, they're packed close together. Whereas in the spongy misophil, there are large gaps. This is to allow gas to fill them so that we can actually have gas exchange. So, we have large air spaces, large spaces between cells. And it does say explain. So you have to say why why is this important to allow gases to diffuse or move through the leaf so they can leaf the cell. Get it? Anyways, um which allows uh photosynthesis in in in layer B or tissue B. Um actually no to or from to or from um cell B. Right? So the idea is that you can have carbon dioxide coming in and oxygen going out at all times because tissues B is where photosynthesis takes place. Figure five shows a pair of guard cells around a stor. Cool. During the day, glucose is made in the guard cells. Describe how an increase in glucose concentration in the guard cells causes the stor to open. Well, um, did I miss a question? Oh, whoops, missed a question. The zylm is adapted to transport water through a plant. Explain one way xyllem is adapted for its function. Well, first of all, it's composed of hollow tubes. Why do they have have to be hollow? Well, to allow water to pass through, right? Again, think of it like a giant straw. If your straw had stuff inside it, water is not going to be able to pass through the straw or any liquid. So, it's composed of hollow tubes to not obstruct water flow. Um it does just say explain one method but sorry one way that it's adapted but some others is uh it has lignon to keep the um keep it open again for the same reason with the straw that's why paper straws suck because they don't stay open right um it has no end walls to allow water to flow easily as well now onto the question I was talking about um so how an increase in glucose concentration in the guard cell causes the stor to open so first of is how does the concentration change? Well, water enters the guard cell via osmosis. Cool. And what happens here is it causes the cell walls to swell and curve at the same time which opens the stor. So if you'd like imagine you're trying to squeeze these like if you pinch them slightly you can imagine that the hole will get bigger, right? the stone will get bigger. That's essentially what happens. So the cells swell and curve to open stor. So when the water enters the guard cell that lowers the glucose concentration. Light intensity varies during 24 hours. Shocking. Figure six shows the overall exchange of carb ducts and oxygen for a tree at three different light intensities. So bright light you have CO2 coming in, oxygen going out. Dim light, it looks like nothing's happening, but there is something happening, but I'm not going to explain it just yet. And no light is where oxygen comes in and carbon dioxide goes out. So explain these different things. So since it's six marks, I'm probably going to put two for each of these. Okay. So, let's get started, shall we? So, let's start with bright light. Let's just go right to left. Right to left. Left to right. Good lord. So, bright light. What happens? Well, as you can see, the overall CO2 is coming in and oxygen is leaving. So overall C CO2 enters the tree and oxygen let's just try oxygen leaves the tree. This is because at high light intensities, the rate of photosynthesis is much higher than the rate of respiration. So again, when you're thinking about these kinds of gas exchanges, always think about what processes. So what process takes in CO2 and produces oxygen is photosynthesis. And here what process takes in oxygen and releases CO2? It's respiration. So on this side we have photosynthesis dominant. It's at a much higher rate than respiration. Whereas in no light respiration is dominant. So now what do you think it is in dim light? Well, it's not. They're balanced. So the rate of photosynthesis and the rate of respiration is basically equal which means there's no overall change in oxygen or CO2 because every bit of oxygen that goes in is then changed into CO2 and every bit of CO2 that comes in is changed into O2. So you have this balance. So the rate of carbon dioxide forming is the same as the rate of oxygen forming. And when I say the same, it's virtually the same. Whereas here it's photosynthesis is dominant. So we're producing a lot more oxygen than we are using. So continue with that. We I basically just explained the rest of the question as well. So dim light overall there is no change in um gas exchange. This is because the rate of photosynthesis is equal to the rate of respiration. So in other words, oxygen is used up just as fast as it's produced and carbon dioxide is used up just as fast as it's produced. And then with no light, when we think about it, there's going to be no photosynthesis. So overall, um CO2 leaves the tree and oxygen enters the tree. This is because the rate of respiration is far higher than the rate of of photosynthesis. There we go. Perfect for six marks. Not really that bad of a question. AMA is an enzyme that digests starch in the digestive system. Why does starch have to be digested? Well, first it might help to think about what it's digested into. So starch is broken down into glucose and other sugars, but glucose. Why is that better? Well, the reason is because glucose is a much smaller molecule and it can dissolve. So it can actually pass into your blood, which is where we need it to be. Whereas starch is large and insoluble. So starch large and insoluble and so must be broken down actually no so cannot be be absorbed into blood. Right? Again that's why you break it down to glucose which is soluble. Boy this looks like a lot. um uses a color col color calorimeter to investigate the rate of starch digestion. It measures the percentage of light passing through a liquid. The darker the color of liquid the less light passes through. So the logic here is if you think about it starch can't dissolve whereas glucose can which means initially you won't be a not much light will pass through the liquid because there's lots of starch in it. Starch doesn't dissolve so it doesn't break apart. But then as it's turned into glucose, you're going to get more light passing through it. Okay. So again, concentration of starch increasing, percentage of light passing through decreases. Makes sense. Yeah. Suggest what liquid was used for the test with 0 g per decime cubed of starch concentration? Um, so again, actually I didn't read the whole thing. So they mix 1 cm cubed of starch with 10 cm cubed of iodine and then measures the pipe percentage. Okay, cool. So then it would probably be the initial amount, right? Yeah. For the 0 g per decime cubed, it was probably 1 cm cubed of starch with sorry, not starch, water. So 1 cm cubed water. Do we need to write the iodine? Yeah, probably. And 10 cm cubed. Was it 10 centimeters cubed? Yes. Of iodine. So again, in order to have zero starch concentration, it means there was no starch, which means they probably just used water. Three, explain the change in the percentage of light passing through different concentration of starch suspension in iodine solution. So basically um already did this, but let's go through it. So if you look, it's like this exponential decrease. to decreases extremely quickly for small increases and then it slowly levels off. So we need to explain why that is. Well, first of all, the percentage of light passing through the liquid decreased with increasing starch concentration. So don't forget when it says explain, you also need to state what the change is in the first place. Now why is this? Well, they've mixed iodine. What color does iodine turn when you mix starch into with it? Well, it turns into like a dark purpley color, right? Or black color. So, simply put, the more starch concentration, the darker the liquid. So because the iodine solution was darker in color and what hap and if you remember your physics dark anything anything dark will absorb more light right that's why if you paint something black it gets very hot and you paint something white it doesn't get as hot because black absorbs lots of light white doesn't the student then investigated the rate of starch digestion using amulets this the method. So they put 10 cm cubed of starch suspension into a test tube. Put 5 cm cubed of amalay solution into a separate test tube. They put both the test tubes into a water bath at 37° for 10 minutes. Then they mix the contents. So again, for those 10 minutes, nothing's happening. Well, the experiment hasn't started yet. Let's put it that way. Then they put the beaker into the water bath, remove a cime cubed of liquid, and add it to iodine solution, measure percentage of light, so on. So the question is why were they kept in the water bath for 10 minutes before being mixed together? What effect would that have? So what would happen if you put the test tubes into the water bath for 10 minutes? Well, initially the test tubes are not at 37°. They're at room temperature which might be around 20°. So when you put them into the water bath, they will start to heat up until they get to 37° C. Why is that important? Well, 37° is the optimum temperature for anal. So, it's basically to make it a fair test by ensuring that they're both at the optimum temperature. So, to get them to reach 37°, which technically is enough to get you the mark, but it's so they'll be at the same temperature or at the optimum temperature as well. That's the more technical reason. Figure eight shows the results. Cool. So it's increasing instead. Fair enough. Concentration of starch at 3 minutes was.3 g per decimate cubed. Calculate the mean rate of starch. Mean rate of starch digestion for the first 3 minutes using figure 7 and figure eight. Okay. So cost at 3 minutes was.3 grams per me cubed. Let's have a look. three minutes. Okay, cool. And then what was the other figure? Figure seven they wanted us to use, right? This one. Oh boy, I love it when I have to scroll back and forth. Actually, wait, what did this one say again? So.3 g per cime cubed. So, we're probably going to have to use the percentage of light here and then use that to work out the percent the amount of time that it's been in there. Okay, got it. Cool. So the mean rate means that we're going to be dividing by a time because again rate always refers to time. So let's see what we'd have to do. Okay, so let's get started with this. So we want to work out the change in concentration and divide it by time. The good news is we can just divide it by three because the time is going to be three. We know that at 3 minutes it ends up at 0.3. So we're going to do minus 0.3. All we need to do is work out the initial amounts. Now, so if we look at initial amount, let's go to time t equals 0. That is 10%. And then we want to get a concentration from that, which means we need to go all the way back to the first one. And we're going to read off 10% here to work out what concentration would give us that. So if we go along, that looks to be about so it goes up in point 2's, right? 6.2 46 8. Yeah. Okay. So that's 6.6. So go all the way down here and we're just doing this is actually a fairly hard calculation to be honest. Well, the calculation isn't hard, but the actual process is. So again, if you noticed, I've taken the difference in the concentrations, dividing it by three because that's what they've asked me for, right? Which is 2.1 g per decime cubed. That's um yeah, that's kind of depressing. That's a bit difficult, not going to lie. The investigation was carried out at PH7. Cool. Explain how the results will be different if the if the investigation was carried out at pH1. Use figure 8. So we're going to have something from here at some point. Well, if it's at pH1, what will happen? Well, first of all, the active site changes shape because it's been denatured, right? This means that starch will not be digested. Not be digested. And well, what does that mean? What would the results be then? Well, if you look back here, initially the percentage of light passing through the mixture was still 10% anyway. So, it would just stay at 10%. So, it would stay percentage of light remains at 10%. That's what would happen. And don't forget when you're talking about the results, you're not just talking about the science behind it. Because bear in mind, you can't see this. That's not what you see. What we see is what we measure, which is how the percentage of light changes. So that's what you need to keep in mind with those questions. Antibiotics are drugs used to treat bacterial infections. Mutations in bacteria produce new strains. Some strains of bacteria are resistant to antibiotics. Where do the mutations happen in bacterial cells? You can say anything from plasmid, chromosomes or DNA all work, which is nice. I would recommend just saying DNA or genes because that's where mutations happen in every single organisms that have DNA, right? So that might be the easiest one to remember. A scientist investigates which antibiotics A, B, C, D, and E killed Sorius bacteria. So they grow in a petri dish. They cut five small discs of paper. They soak them in different antibiotic solutions. They put them into a petri dish and they keep it at 37 degrees for 24 hours. 37 degrees because that's like the most prolific uh growth rate for this bacteria. And any blank spots is basically dead bacteria, right? So E and C, they had no effect on this bacteria. But D had a little bit of an effect. Then A and it looks like B has the biggest clear spot. So that means it would be the most effective. The scientist concluded S orius is resistant to C and E. Makes sense. Explain the evidence. Well, there's no clear area. What is happening? Area around C and E, which means that there was no bacteria killed. That's why it's antibi antibiotic resistant, right? Because there's no bacteria killed. The scientists later discovered that Sorius is not resistant to antibiotic E. Suggest how the method was developed and showed where it's not resistant. So what do you think they would have changed? Well, when you think about medicine, it's not just what medicine you take that has an impact, right? It's also the concentration. So for example, you might take a little bit of paracetamol and not feel better, but if you take a higher concentration of paracetamol, you might well feel better, right? That's because different concentrations of medicines also have an impact. So what probably happened is they used a higher concentration of antibiotic E and then observed that there was a clear area around the disc. That's probably what happened. Cool. Broken bones are sometimes repaired using a metal implant. Cool. The area around an implant can become affected with this bacteria. The infection is usually treated with a long-term course of antibiotics. Long-term use of antibiotics has led to the development of antibiotic resistant bacteria. Different treatments called stems from bone marrow and from fat tissue have microbial properties. A scientist investigated the effect of four treatments on the area around infection. Each treatment was injected into the area around the implant. So the four treatments were unreactive solution, antibiotic solution, stem cells from fat tissue, stem cells from fat tissue containing antibiotic and is treated on five patients when infection had developed. After 7 days, the um scientists calculate the ratio of the area of infection over the total area. Bloody hell. So what was the independent variable in the investigation? So what was the thing that the scientist changed? it was the treatment itself. Right? These two things would have been control variables. And this here is the dependent variable because it's what you're measuring. So again, dependent variable is what you measure. What's the outcome? The independent variable is what you change. Yeah. Is what you change actually. That's it. Suggest one advantage of using stem cells from fat tissue rather than stem cells from bone marrow. Well, here's the key thing. Where do you get bone marrow from? You get it from inside bones, right? Which means to get bone marrow from anywhere in your body, they need to drill into your bones and extract it, which is painful and it's also difficult. Whereas fat is a lot easier to obtain. So, simply put, you can either say it's easier to obtain or less invasive. I'm going to say easier to obtain. Um, you can also say it's quicker as well because again you don't have to drill into someone's bones. Stem cells containing antibiotics were produced by growing the cells for 24 hours in a solution containing the antibiotic. How did the antibiotic enter the stem cell from the solution? Active transport, diffusion, osmosis, transllocation. Well, let's think about it. Active transport happens when you go against a concentration gradient. So that would mean the amount of antibiotic inside the cell already is bigger than the number the amount of antibiotic outside the cell. Does that make any sense? No. Right? Because in the solution containing the antibiotic, there should be loads of the antibiotic. Right? Absolutely loads of it. So it's not that it's not osmosis because it's not water transllocation. Not quite. It is diffusion. Why? Because the concentration of antibiotic is lower inside the cell than outside the cell. Classic shows the results. So unreactive solution and blah blah blah. What is the range of results for the treatment with stem cells only? You're literally taking the difference between these two values, right? The biggest possible value and the smallest one. The biggest one, it looks like it's 0.31. And the lowest one is 09. Not 99. Yeah. Cool. Then lastly, soon looked at the results and concluded injections of stem cells containing antibiotics should be used to treat all implant related infections. Evaluate his conclusion. So basically, this is where you're saying pros and cons. You're not saying if it's good or bad. You're saying the good side and the bad side. Okay? So I can see why he would say that because if you look at it, it seems to have had the smallest ratio just even in terms of a range. So that's valid. Although for some the antibiotic solution might be better because again but think about why that might be better or worse, right? Bear in mind the stem cells you have to gain them get them from somewhere. That's quite expensive and invasive whereas just the antibiotic solution should be quite easy. So for some infections it might be better idea just use antibiotic solution. That's the kind of idea that you're doing. Okay. So let's talk about pros and cons. In fact, I don't need that yet. So, pros and cons. Pros is um treatment had the smallest area of infection and the smallest range of results. That means it's more reliable, right? So, again, with the antibiotic solution, look at the range. So, sometimes it works really well, sometimes it barely worked at all. If you're taking a treatment, right, you want it to work 99% of the time, right, which this one does. Uh, whoops. Um, it also has no overlap with the unreactive solution, right? So, bear in mind this is what happens if you just let nature take its course, so to speak. So, because there's no overlap, it suggests that it always works. So, no overlap with unreactive solution. therefore um suggests it's always effective. So when I say always effective, it doesn't mean it always works 100% but it always has an impact. Now let's talk about the cons. Uh because don't forget when you're doing evaluation, you need to have a couple of pros, a couple of cons. Just so you're aware, it's two of each. If it was a six mark question, it' be three of each. Okay? So we're doing two pros, two cons. I've given you three pros. So what are like the biggest cons? Well, the first thing is if you look way back in the beginning of this, it says that they only did it with five people, which it's not exactly a big sample size. So, small sample size, five people. Uh, what else could we say? Um, as I said before, antibiotic solution did have similar results to the stem cells containing antibiotic and it also has similar results to the stem cells only. So it doesn't mean that it should be used all the time. Uh similar results to stem cells only. Um yeah, and that'll probably be be fine. Bear in mind that when you use an antibiotic, you're always going to run the risk of creating antibiotic resistant bacteria, which is a really really big issue. So if we can get away with just using stem cells, why not just use stem cells, right? Why risk the And again, the difference here is between 0.09 09 and like what 0.03. It's a very small difference. So, it might be worth just doing the stem cells only. But anyways, that brings us to the end of the paper. 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