Question

answer this question

Answer 1

i) because thick wall help them to withstand and absorb the pressure waves which begin in the heart and are transmitted by the blood.

ii) because the blood that is carried from the heart to the capillaries has more high pressure.As the blood flowing through the vein does nat have much pressure as in that of the arteries their walls are thinner as compared to artery walls

iii) because they ensure blood flows in only one direction.Valves also help blood travel back to the heart against the force of gravity.