Demand of oxygen in water does not increase with increase in a/concentration of solid waste
b/number of aquatic plants
c/number of aquatic animals
d/rapid flow of water

b. number of aquatic plants

Explanation:

The number of aquatic plants doesn't increase the demand for oxygen in water because these plants take in carbon dioxide rather than oxygen. This means that an increase in their number will not trigger an increase demand for oxygen, rather it will trigger an increase demand for carbon dioxide in its dissolved form.

An increase in the concentration of solid waste, increases the demand for oxygen because it is needed for decomposition.

An increase in aquatic animals will increase the demand for oxygen in its dissolved form because aquatic animals take in oxygen to survive.

An increase in the flow of water increases the demand for oxygen because as water flows, it mixes with air. The more rapid it is, the higher the chance to mix with oxygen.

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.