30 !
which statement accurately describes the tissues indicated by the arrow in the microscopic image?
the connective tissues that protects the outside of the veins
the connective tissues that protects the inside the veins
the endothelium on the inside of the artery
the smooth muscle on the outside of the artery

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.

because photosynthesis could not occur (apex)