well depends what your doing :D
All of them. That's why they exist.
nervous system
The central nervous system.
No, all organisms react to their environment to survive.
Respond
There are 7 characteristics of life one of which is irritability, meaning an organism needs to be able to react to its environment, this characteristic or instinct is what causes organisms to react to their environment. The ability to ajust to this change in their environment is adaption.
There are 7 characteristics of life one of which is irritability, meaning an organism needs to be able to react to its environment, this characteristic or instinct is what causes organisms to react to their environment. The ability to ajust to this change in their environment is adaption.
hahaha
Your senses enable you to react to your environment. They allow you to pick up on smells, sights, feelings, etc.
the body does not react well to bacteria. It can be harmful to your body and can start disease
Nerves serve two functions for the body. They give orders to the brain that direct organs and tissues and they send signals about the body's condition or environment to the brain, directing the body to react.
Rainwater.