Living organisms need a system of control and coordination to survive and function effectively in their environment. Every moment, organisms encounter various changes in their surroundings, and they must respond appropriately to maintain their well-being.

The primary need arises because all movements in response to the environment must be carefully controlled. Each kind of change in the environment evokes an appropriate movement in response. For example, when we want to talk to friends in class, we whisper rather than shouting loudly. This shows that the movement to be made depends on the event that is triggering it.

Control and coordination systems ensure that organisms can recognize various events in the environment and then make only the correct movement in response. Without such a system, organisms would not be able to respond appropriately to different stimuli, which could lead to harmful consequences.

In multicellular organisms, specialized tissues are used to provide these control and coordination activities. In animals, this function is carried out by nervous and muscular tissues. The nervous system uses electrical impulses to transmit messages and gets information from sense organs to act through muscles. Additionally, hormones provide chemical coordination in both plants and animals.

Thus, a system of control and coordination is essential for organisms to survive, grow, develop, and respond appropriately to their ever-changing environment.