Amodel organism is a species that researchers study to better understand certain biological process mollusks and arthropoda are commonly used as model organisms for studying mechanisms of learning and memory , while sponges and jellyfish are not why this?

Both arthropods and mollusks possess cephalization, while sponges and jellyfish do not.

Explanation:

The processes of memory and learning are the functions of the brain. Cephalization refers to the procedure of concentration of sensory composition and development of head in organisms. The sponges and jellyfishes are the radially symmetrical species with no cephalization. The flatworms were the first to possess certain cephalization. The arthropods and mollusks are the species that possess greater extent of cephalization and thus are used as model organisms in order to examine the mechanisms of memory and learning.

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.