Question

1. Write the function of valves in veins .

Answer 1

Answer:

1.

•After the left ventricle contracts, the aortic valve closes and the mitral valve opens, to allow blood to flow from the left atrium into the left ventricle.

•As the left atrium contracts, more blood flows into the left ventricle.

•When the left ventricle contracts again, the mitral valve closes and the aortic valve opens, so blood flows into the aorta.

2.

•Diffusion is defined as the movement of individual molecules of a substance through a semipermeable barrier from an area of higher concentration to an area of lower concentration.

Explanation:

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