Explain the importance of irritability in organisms.

Irritability – the ability of living organisms to respond to changes in the external environment, is an integral property of living things. Only if this sign is present, it can be determined that the organism is alive. In the simplest organisms and plants that do not have a nervous system, irritability performs its function. It allows you to avoid negative environmental influences and to adapt to them. At the same time, physiological and physicochemical processes change in the body.