The material present in arterioles that is not present in capillaries is
(A) a lining of endothelial cells.
(B) white blood cells and platelets.
(C) fully oxygenated blood.
(D) circular smooth muscle cells that can alter the size of the arterioles.
(E) plasma in which carbon dioxide has been added.

The ancestors of plants that lived in water had plenty of water for the young. angiosperms are a group of land plants that evolved a reproductive trait for living on land. this trait protect young plants by allowing them to grow only when water is present and the conditions for healthy development are right. what trait most likely young angiosperms in this way?