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A level Biology: Post your doubts here!

confused123

confused123

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hmlahori said:
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w06_qp_2.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w06_ms_2.pdf
question 1 (a) why cant the answer be B(population) for 'mangrove trees'. is it because it doesnt mention "all" the mangrove trees in the swamp?
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it says mangrove trees but there must be a lot of variation and types of trees found between mangrove trees. even if you right B population then its not wrong because you can use one term twice.
 
S

Soulgamer

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confused123 said:
it says mangrove trees but there must be a lot of variation and types of trees found between mangrove trees. even if you right B population then its not wrong because you can use one term twice.
Click to expand...

Yes its because it just said mangrove trees, not all the mangrove trees in the area.
 
littlecloud11

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confused123 said:
http://www.xtremepapers.com/CIE/International A And AS Level/9700 - Biology/9700_s08_ms_32.pdf
q.2 iv part can someone plz draw the high power diagram for this part. or guide me how exactly to draw in this part
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There should be no inter cellular spaces as the question clearly states that the cells should be in contact. And the collective length of the drawing in any direction should be more that 7-8 cm.
the companion cell should be less 1/4 of the sieve tube as the mark scheme states. as this is a high power diagram you have to show not only the outline of the cells but also the visible components. No other cell organelles except for the nucleus should be shown as the diagram of the slide given doesn't show any. And labels are optional as the question doesn't ask for any.

All other basic rules, such as no shading, no broken lines etc. are applicable here.
 

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confused123

confused123

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littlecloud11 said:
There should be no inter cellular spaces as the question clearly states that the cells should be in contact. And the collective length of the drawing in any direction should be more that 7-8 cm.
the companion cell should be less 1/4 of the sieve tube as the mark scheme states. as this is a high power diagram you have to show not only the outline of the cells but also the visible components. No other cell organelles except for the nucleus should be shown as the diagram of the slide given doesn't show any. And labels are optional as the question doesn't ask for any.

All other basic rules, such as no shading, no broken lines etc. are applicable here.
Click to expand...
Thanks a loooot!
 
Saad (سعد)

Saad (سعد)

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As-Salaamu 'Alaykum.

Any tips on what we should be careful of when performing the Bio Practical exam, and on what we should do for preparation, since there's only 1 day left now for Bio 34? Not asking for a guess paper or anything, just some general tips on what we should revise on the last day.

Also, anyone have 'Examiner Tips' for Bio AS and A Levels? I found Tips of Chem and Physics but no Bio. :eek:
 
narutogirl

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Hi, I have my practical tomorrow, paper 32
I am not asking for any guesses ^_^""
I just have trouble with drawing the alveoli and the aorta, if anybody could draw them, I would be very greatful ^_^
Also I have a general question, in the cambridge book (the black book) the artery appears to have a larger tunica externa. Now I am very confused about the matter. which is thicker in the artery ? the tunica media or the tunica externa and is it the same thing in the aorta, because it is written that the aorta has a thick tunica intema while the artery doesn't...:/
A much clearer question, what is the difference between the aorta and the artery ?
 
confused123

confused123

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narutogirl said:
Hi, I have my practical tomorrow, paper 32
I am not asking for any guesses ^_^""
I just have trouble with drawing the alveoli and the aorta, if anybody could draw them, I would be very greatful ^_^
Also I have a general question, in the cambridge book (the black book) the artery appears to have a larger tunica externa. Now I am very confused about the matter. which is thicker in the artery ? the tunica media or the tunica externa and is it the same thing in the aorta, because it is written that the aorta has a thick tunica intema while the artery doesn't...:/
A much clearer question, what is the difference between the aorta and the artery ?
Click to expand...


aorta has to withstand high blood pressures so it must have a thicker tunica intima and more elastic tissue and fibrous tissue as compared to any other artery.
tunica externa is thicker in artery then the tunica externa of a vein. tunica media is thinner in vein as compared to an artery.
 
Saad (سعد)

Saad (سعد)

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Okay, this may sound like a really, really dumb question.

But someone please tell me... how do you annotate a diagram? I've almost completed my AS-Levels but I still don't understand what annotation even means. >.<
 
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