The blue areas in the image represent the body parts that transport deoxygenated blood throughout the body. what are they called "?

The answer is veins. Veins carry blood from tissues to the heart. The vena cava is the largest vein in the body that carries blood into the heart right auricle. Pulmonary vein  is the only vein that carries oxygenated blood because it carries blood from the lungs to the heart.

cell division is not regulated in tumor cells.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.