Animals have a nervous system for controlling and coordinating body activities, while plants lack both a nervous system and muscles.

The simplest notion of movement at the cellular level in muscle cells is that they move by changing their shape, leading to a shortening of the muscle cell.

When a nerve impulse reaches the muscle, the muscle fiber moves by changing its shape, specifically by shortening.

The final job performed by muscle tissue, in response to nervous impulses, is to execute actions or movements.

If the cerebellum failed to function, activities like walking in a straight line, riding a bicycle, and picking up a pencil would lack precision and coordination. Individuals might experience difficulties in maintaining balance and performing these actions smoothly.