Answer the following question given this paragraph: 

The human nerve cell in Figure below is a good example of a specialized animal cell. Its shape suits it for its function of sending nerve signals to other cells. A nerve cell couldn’t take this shape if it were surrounded by a rigid cell wall.


Q: With a shape that specially suits its function of sending nerve signals to other cells, the human nerve cell is an example of what?

 Choices:

- adaptation

- maturation

- evolution

- specialization

A:
specialization
