The reason why the flow of blood through the capillaries is very slow is
- because the walls of Capillaries are very thick
- to avoid high blood pressure
- to ensure that the individual does not get dizzy
-
Their large numbers and one cell-thick walls enables them to provide a large surface area through which materials can be exchanged between the blood and the body cells.
The correct answer is: D
Explanation
Their large numbers and one cell-thick walls enables them to provide a large surface area through which materials can be exchanged between the blood and the body cells.
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