Structural organisation in animals attains different levels as cell-organ-organ system. What is missing in this chain ? Mention the significance of such an organisation.

Explanation

Many cells unite to form a tissue. Many tissues unite to form an organ and many organs unite to form organ system. The body is made up of thousands of cells in Hydra in which each cell works independently while in complex body system (eg. human) crores of cells unite and do various functions w hich are connected to each other by connective tissue.