Plant cells are also able to become longer as they grow. This process is called cell elongation and occurs throughout the plant, not just in the meristems. Cell elongation does not occur in animals.

Circulatory system Transport substances. Defend the body. Regulate temperature. Excretory system Remove waste products and unwanted substances. Regulate the water content of the body. Muscular ...

For example, the endothelial tissue that lines the human gastrointestinal tract consists of several cell types. Some of these cells absorb nutrients from the digestive contents, whereas others ...