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# Edexcel Biology IGCSE 2B Unofficial Mark Scheme 10th June 2016 watch

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1. what would 124 marks be as a grade, if you were to assume
2. (Original post by Hsevras)
what would 124 marks be as a grade, if you were to assume
It should be an A
3. (Original post by y64654)
You got it correct- the point of the question is to identify the fact that no matter how many children you have the probability resets. Well done
I asked my teacher and he said, as a probability, it is 0.125 (out of 1) or 12.5%. 50% is wrong
4. No your wrong, it said the probability of ALL 3 therefore 50^3
5. i put 1/8 not 0.125 or 12.5%, reckon I'll still get the mark?
6. (Original post by jose99)
i put 1/8 not 0.125 or 12.5%, reckon I'll still get the mark?
yea, 1/8 is the same as 0.125
7. (Original post by rcmack)
yea, 1/8 is the same as 0.125
Nice one, thought so
8. (Original post by escg)
guys could someone please clear up 4b for me, its killing me. I put the first deer because if you divided the mass by the days (or the other way round can't remember lol) then it gave you how many days it took for a kg of the deer to grow. By that calculation the first one took like 16 days and the second one took 6 (can't remember exactly) then the rest were less than 6. So that's why I put the first one, did anyone do the same? Please tell me they did lol.
No it was defo the roe deer because both the roe and one of the others sika i think had a mass of 35kg but sika was 217 days and roe was 294 days so for the same mass roe took 77 days longer and in the question it talked about staying dormant for a few moths and 77 days is rougly 2 and a half months
9. (Original post by rcmack)
im pretty sure that you just said that the roe was a lot longer that the sika, which had the same mass of 45kg (i think). this means, as the result does not fit the general pattern of results, so the embryo had to remain inactive
35kg - it was inactive for 77 ish days.
(Original post by y64654)
You got it correct- the point of the question is to identify the fact that no matter how many children you have the probability resets. Well done
No-it asked the probability of having three children with the disease. One child = 0.5. Two children = 0.5^2. Three children 0.5^3 = 0.125.
(Original post by jshwan)
I got that genetic probability question wrong. Can someone actually explain how having 3 children with the disease is more unlikely than having 1? I might be overthinking, but I thought it was 50%.
it asked the probability of having three children with the disease. One child = 0.5. Two children = 0.5^2. Three children 0.5^3 = 0.125.
10. (Original post by rcmack)
It should be an A
Yup, that mark is bang in the middle of an A
- good job!

(Original post by nikhilpatel99)
For the fish vaccination could you argue:
- More vaccinated fish = less death from diease
- So less decomposers present to feed on dead fish
- So less oxygen used up by decomposers
- Thus more oxygen available in the water for fish
- So more respiration and growth is healthy

Idk just what i put i think it might be wrong tho
Yeah i dont think thats right -
This mark scheme is right - however you needed to have said that because it doesn't get a disease, it uses all its energy to eat and grow, rather than to fight off illness to get the final mark to relate it to the question.

3)C) had to talk about the fact that he fromed an AVERAGE of the ten results.

For the question about the factors effecting time duration to digest the insect I put size of insect and what the insect is made up of - because different proteins/tissues take different lengths of time to breakdwon - will i get any marks - what you guys think?
11. (Original post by Martins1)
Yup, that mark is bang in the middle of an A
- good job!

Yeah i dont think thats right -
This mark scheme is right - however you needed to have said that because it doesn't get a disease, it uses all its energy to eat and grow, rather than to fight off illness to get the final mark to relate it to the question.

3)C) had to talk about the fact that he fromed an AVERAGE of the ten results.

For the question about the factors effecting time duration to digest the insect I put size of insect and what the insect is made up of - because different proteins/tissues take different lengths of time to breakdwon - will i get any marks - what you guys think?
mmm im not sure, it makes sense but they might be after reasons relating to rate of digestion, so pH and temperature for enzymes, not the size of the food
12. (Original post by rcmack)
mmm im not sure, it makes sense but they might be after reasons relating to rate of digestion, so pH and temperature for enzymes, not the size of the food
but surely the amount of food to be digested will affect the time?
13. To be honest I'm dropping biology and I'm confident i got a strong A* so I'm not gonna worry - just wondering.
One thing i was surprised at was that over the two papers there was no kidneys, nitrogen/carbon cycle, fermenters/yoghurt/beer or lungs, very little circulation and very little digestion or plant reproduction (or structure of a plant?), but so much of human reproduction and eye...
14. couldnt you mention the fact that less water is lost from the soil as black absorbs it all, meaning more water is available for photosynthesis to occur, as if light rays had direct contact with the soil, the temperature of the soil would increase and so water would evaporate
15. (Original post by Martins1)
To be honest I'm dropping biology and I'm confident i got a strong A* so I'm not gonna worry - just wondering.
One thing i was surprised at was that over the two papers there was no kidneys, nitrogen/carbon cycle, fermenters/yoghurt/beer or lungs, very little circulation and very little digestion or plant reproduction (or structure of a plant?), but so much of human reproduction and eye...
no heart either!
16. I put fovea not retina! Will I get the mark d'you reckon?
17. Anyone have a clue about what the grade boundaries will be like for the Biology Igcse papers edexcel?
18. (Original post by Martins1)
35kg - it was inactive for 77 ish days.

No-it asked the probability of having three children with the disease. One child = 0.5. Two children = 0.5^2. Three children 0.5^3 = 0.125.

it asked the probability of having three children with the disease. One child = 0.5. Two children = 0.5^2. Three children 0.5^3 = 0.125.
Don't think it asked for kids with the disease, it just wanted probability of having having a boy
19. (Original post by rcmack)
i think the dominant allele caused the condition, so DD and Dd were infected
there weren't any homozygous dominants, if they had the condition they were only heterozygous dominant cause no parents on family tree both had Hh
20. (Original post by escg)
Guys, for 4b) I put the first deer because if you divided the mass by the days (or the other way round can't remember lol) then it gave you how many days it took for a kg of the deer to grow. By that calculation the first one took like 16 days and the second one took 6 (can't remember exactly) then the rest were less than 6. So that's why I put the first one, did anyone do the same? Please tell me they did lol.
you over thought the question

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