A level Biology: Post your doubts here!

[saturn21]

To see the greatest number of cells the magnification should be low...so out of all...A has the lowest magnification...which means the image is not magnified that much

 

[qwertypoiu]

I remember solving this question...and the answer was 80 (C)

I see that's good. Thanks for telling me.

 

[qdkhan]

32 help!!

it is C because CO combines irreversibly wd Hb< preventing it from combining wd Hb. So it shdnt really have any effect on diffusion rate of oxygen and CO cannot prevent oxygen release anyhow

 

[saturn21]

Variant 11 May June 12 Q40.....HELP ME PLZZZZ!

The answer is B
they told you that net.... is gross productivity-respiration
they told you the net productivity for producer which is 1.8 and then for herbivore (primary consumer) is 0.75...so the amount of energy passing from producer to herbivore is 0.75/1.8


Let me know if i am wrong

 

[Lola_sweet]

Variant 11 May June 12 Q40.....HELP ME PLZZZZ!

is this qs in our syllabus people?

 

[saturn21]

question 37 )

 

[saturn21]

is this qs in our syllabus people?

Yup..i guess so

 

[princess Anu]

but the ans is D

it is C because CO combines irreversibly wd Hb< preventing it from combining wd Hb. So it shdnt really have any effect on diffusion rate of oxygen and CO cannot prevent oxygen release anyhow

 

[qdkhan]

can anyone please help me with q25, q31, 33 and 39?
in 33, shdnt C be the answer cz patients can be yunger than 30. In 39, is A d answer cz soil condiditons donot really make a difference to nitrogen fixing bacteria as dey r in d nodules?
http://onlineexamhelp.com/wp-content/uploads/2013/10/9700_s13_qp_11.pdf
http://onlineexamhelp.com/wp-content/uploads/2013/10/9700_s13_ms_11.pdf

 

[qdkhan]

but the ans is D

check d answer agn, it is C. i jst dd

 

[qdkhan]

View attachment 53271

question 37 )

th answer is A(A and AB) cz if O and B blood grp ppl receive A grp blood, they wd produce antibodies agnst A blood cells cz A antigens wd be recognised as foreign.

 

[saturn21]

th answer is A(A and AB) cz if O and B blood grp ppl receive A grp blood, they wd produce antibodies agnst A blood cells cz A antigens wd be recognised as foreign.

Ohhhhh...thanks alot

 

[saturn21]

Question 5..Why is the answer C and not B?

 

[Studydayandnight]

How do we solve this???

Correct answer is A.

 

[qdkhan]

View attachment 53272

Question 5..Why is the answer C and not B?

5th ryt? B is wrong bcz both mitochondria and chloroplasts have 70S ribosomes similar to that in prokaryotes. C is correct cz all mitochondria, chloroplasts and prokaryotes have small circular DNA molecules.

 

[qdkhan]

How do we solve this???

Correct answer is A.

see d pollen grain at the far left had its pollen tube growing parallel to the eyepiece graticule so we calculate the increase in its length ovr d 4 hr period, which is 8 divisions.
50 divisions on graticule>0.1 mm
1 division>0.002 mm
so increase in pollen tube's length= 8 * 0.002=0.016 mm
growth rate= increse in length / time= 0.016/4= 4*10-3(10 raised to the power of -3)mm/hour.
if we convert this to micrometer per hour by multiplying it by 1000, we get 4 micrometers per hour and dis is kinda close wd A and so dis will be d answer

 

[shazmina]

Can any1 pls help me with this question ...
https://www.xtremepapers.com/community/attachments/bio-mcq-jun-2010-p11-png.51946/
the ans for it is B

 

[qdkhan]

Can any1 pls help me with this question ...
https://www.xtremepapers.com/community/attachments/bio-mcq-jun-2010-p11-png.51946/
the ans for it is B

P represents the contraction of the atrial walls, so it rrepresents the excitation wave sweeping ovr the atrial walls in response to which they contract. Q,R and S represent the wave sweeping ovr the ventricular walls which cause them to contract, and T represents the rrecovery of the ventricle walls. there is explaination on dis on Pg 170 in the AS bio book by Mary jones, Dennis taylor, richard fosbery and jennifer gregory.

 

[qdkhan]

can anyone please help me with q25, q31, 33 and 39?
in 33, shdnt C be the answer cz patients can be yunger than 30. In 39, is A d answer cz soil condiditons donot really make a difference to nitrogen fixing bacteria as dey r in d nodules?
http://onlineexamhelp.com/wp-content/uploads/2013/10/9700_s13_qp_11.pdf
http://onlineexamhelp.com/wp-content/uploads/2013/10/9700_s13_ms_11.pdf

anyone pls!!!

 

[shazmina]

P represents the contraction of the atrial walls, so it rrepresents the excitation wave sweeping ovr the atrial walls in response to which they contract. Q,R and S represent the wave sweeping ovr the ventricular walls which cause them to contract, and T represents the rrecovery of the ventricle walls. there is explaination on dis on Pg 170 in the AS bio book by Mary jones, Dennis taylor, richard fosbery and jennifer gregory.

Thank you so much brother
Well i do have that text book but i think i have the old edition .. caz Pg 170 doesn't talk abt this