Irritability ar sensitivity is a characteristic feature of all living organism and refers to their ability to respond to a stimulus. The stimulus is received by a receptors. It is transmitted by means of nerves or hormones and an effectors brings about a responds.

Definition:coordination refers the series of activities that the body carry out to respond to the external environment. It is generalty refers to as the responds to a stimulus. This activities are controlled by a system known as the central nervous system(CNS) . the central nervous system is made up of the brain and the spiral cord link to this are million of fibre known as neurones. Which are responsible for carrying information to and from the central nervous system. There are two major types of coordination in the body:

Nervous coordination

Hormonal coordination:  however, nervourse coordination involve the movement of the impulses alongs neurone.

HORMONAL COORDINATION IN ANIMALS

In unicellular organism, the cell is so small that information can easily flow from one part of the cell to another. This is not the case with multicellular organism because it is difficult for information from one cell to flow to another distance cell. Hormonal coordination is present in both plant and animal while nervous is present in animal only. Hormonal coordination involve hormones.