Give reason a). Arteries are thick walled blood vessels. b) veins have valves in them.
Answers
Answer:
a) Arteies have thick walls because the blood pressure in them is high and they have to adjust their diameter to maintain the blood flow.
b) Veins have valves in them to prevent the flow of blood in opposite direction.
OR
Veins have valves in them to ensure the unidirectional flow of blood.
Answer:
a). Arteries are thick-walled, muscular vessels that almost always carry oxygenated blood away from the heart. The muscular walls allow the arteries to pulse and help push the blood farther along the circulatory pathway as the blood travels away from the heart.
b). Unlike arteries, veins contain valves that ensure blood flows in only one direction. (Arteries don't require valves because pressure from the heart is so strong that blood is only able to flow in one direction.) Valves also help blood travel back to the heart against the force of gravity.