Answer:

Their muscular walls are thicker than the atria because they have to pump blood out of the heart

Explanation:

This is because the left ventricle has to pump blood at a higher pressure so that it reaches all areas of the body (including the fingers and toes) but the right side only has to pump blood to the lungs.

Explanation:

the ventricle have thick muscular walls because they have to pump blood to long distance