Why do animals need to have a nervous system?

Question

Why do animals need to have a nervous system?

Answer 1

because they are just like human beings they react the same way

Answer 2

It controls all the other systems in the body, and allows them to react with their environment.

Answer 3

Nerves send signals from all parts of the body to the brain and from the brain back to all parts of the body.

For example, a nervous system allows the animal to feel pain, then use its muscles to run away from the cause of the pain.  The brain senses the need for oxygen and makes the breathing faster as the dog runs.  In a flight or fright situation like this, the brain will shut down the digestive system, and send more blood to the muscles and internal organs and less to the skin.  Sensors also tell the brain when the animal is overheating from running so it will stop and cool off.  This is just one simple example, but you can see how all parts of the body are affected and are run by the brain.

Answer 4

Respond to external stimulus, e.g. light, temperature,sound,pain etc. Also it assists with movement.

Answer 5

why not?