F4 BIO MCx3

[匿名]

2012-02-07 10:21 am

1.Which of the following blood vessels can regulate the amount of blood
to a certain organ?
A aorta
B arterioles
C veins
D capillaries

ans:B,WHY NOT A?

2.The graph below shows the changes in two parameter

圖片參考：http://imgcld.yimg.com/8/n/HA08177970/o/701202070010213873435260.jpg

Ans:B.Why not C?

3.Some babies are born with a hole joining the left atrium and the right
atrium.This may

A. cause more blood to enter the left atrium and the right ventricle.

B. cause some blood to bypass the lungs.

C. prevent some blood entering the right atrium.

D. prevent the heart muscle working.
Ans B,why not A?

回答 (1)

Billyionaire

2012-02-09 2:58 am

✔ 最佳答案

1. Answer is B,the question ask you a vessel that can regulate blood to a CERTAIN organ, aorta supply blood to many part of the body, it can't just regulate blood to ONE certain organ!
2.velocity of bloodflow in venule and vein is faster than that in capillaries since muscles around venule and vein push blood back to the heart. It is also because that venule and vein has larger cross-sectional area and thus small friction. second statement in C is wrong.
3. A must be wrong. The amount of blood in circulatory system of a person is constant.

參考: me

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