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A level Biology: Post your doubts here!

M

My Name

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HumptyR said:
Normal venous pressure in the feet is 3.3 kPa. When a person stands very still venous blood
pressure in the feet rises to 5.0 kPa. What causes the high pressure?
A Muscles in the walls of the veins contract, reducing the diameter of the veins.
B Skeletal muscles in the legs are not squeezing blood upward in the veins.
C Systolic blood pressure increases.
D The semilunar valves in the veins of the leg cease to function.
Click to expand...
It will be B.
What is your doubt?
 
nehaoscar

nehaoscar

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HumptyR said:
Normal venous pressure in the feet is 3.3 kPa. When a person stands very still venous blood
pressure in the feet rises to 5.0 kPa. What causes the high pressure?
A Muscles in the walls of the veins contract, reducing the diameter of the veins.
B Skeletal muscles in the legs are not squeezing blood upward in the veins.
C Systolic blood pressure increases.
D The semilunar valves in the veins of the leg cease to function.
Click to expand...
B - since the skeletal muscles in the legs are not squeezing blood upward in the veins, the pressure at the feet would increase as all the blood is flowing towards the feet more rapidly than it is being pushed up away from the feet
 
HumptyR

HumptyR

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nehaoscar said:
B - since the skeletal muscles in the legs are not squeezing blood upward in the veins, the pressure at the feet would increase as all the blood is flowing towards the feet more rapidly than it is being pushed up away from the feet
Click to expand...
Thanks thanks
 
J

Jeed

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AOA Could someone please tell approximately how many days can the Biology syllabus be done from the CIE Endorsed book?
 
M

My Name

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Jeed said:
AOA Could someone please tell approximately how many days can the Biology syllabus be done from the CIE Endorsed book?
Click to expand...
Waalikumasalam warahmatuallah
The answer to your question is that it depends on the person who is studying and how he or she is good at time management.How many other things the student is involved in and blah blah...you know what I mean? :3

Lets see..umm for AS Biology withing about 5 months our class finished the syllabus.I guess.
My reply isnt that helpful it seems. :/ Anyway thats all I have to say.
Best of Luck!
 
Lola_sweet

Lola_sweet

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Can someone please tell me the relation of mutation with haemophilia?
The syllabus asked for albinisim, HE, sickle cell and haemophilia, apart from the latter all r present
So can anyone provide me with some info
 
qwertypoiu

qwertypoiu

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Lola_sweet said:
Can someone please tell me the relation of mutation with haemophilia?
The syllabus asked for albinisim, HE, sickle cell and haemophilia, apart from the latter all r present
So can anyone provide me with some info
Click to expand...
Haemophilia is explained in page 379 of new book. Maybe you don't have that, but thanks to My Name you can see it here:
CIE coursebook for A2 Biology (4th edition for the 2016 syllabus)

The specific image with info on haemophilia is image 16.

If you already understand sex linked inheritance, the diagram in that page should be self explanatory, but if you still have doubts I'll be happy to explain :)
 
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