The nervous system consists of the brain and spinal cord (central nervous system) and the peripheral nervous system which is the network of nerve cells (neurons) that collect and distribute signals from the central nervous system throughout the body.

The cerebrum is the major part of the brain and is responsible for the main senses (thinking, hearing, seeing).

Rising into the atmosphere, the water condenses into clouds. When the clouds become too saturated with water, the water is released as snow or ice precipitation which may warm as it falls to reach Earth as rain.

The narrowest classification of life, species, contains organisms that are so similar that they can only reproduce with others of the same species.

Food is mixed with gastric acid and pepsin in the stomach to help break down protein.