• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

A level Biology: Post your doubts here!

Messages
140
Reaction score
396
Points
73
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
 
Messages
140
Reaction score
396
Points
73
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 :)
 
Messages
23
Reaction score
6
Points
13
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
 
Messages
23
Reaction score
6
Points
13
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.
 
Top