Answer:
The nervous system is stimulated from the environment, through sensory receptors. A stimulus is any form of energy that can be detected by the body. ... Animals normally only respond to stimuli which they select; they filter out certain stimuli that surround them, and react to others they choose to accept.
The enzyme that breaks down H2O2 is called catalase.
It was the plants around us. They give us air to breath. It was to help us breath so we can live.
Contains and protects the cell
