JAMB - Biology (2018 - No. 12)
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.
Forklaring
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.