Irritation in the living

Irritability is the ability of living things respond to stimuli internal and external environment. It is a characteristic of living beings that allows you to survive and eventually adapt to changes in the environment through proper coordination of various body parts. Both plants and animals have regulatory mechanisms in order to adequately respond to external stimuli and internal and thus maintain their structure and physiology, however, there is a difference between them, the animals exist in tissues and organs as specialized nerves and muscles. The plants lack both systems, but these same respond and make adjustments against a changing environment. The strategy includes adaptive plant growth and coordinated development, both for relatively long periods.