HOR ARE ANIMALS ORGANISED?

Cells:
Multicellular organisms have many types of cells. The cells are different shapes according to their function.
Tissue:
Cells join together to form tissue. Each type of tissue has a specific function.
Organs:
Organs are made up of different tissues.
Systems:
Systems are groups of organs that work together to perform a function.

There are many types of cells in multicellular organisms. Each type has a specific function and a unique appearance:
Red blood cells. They are flat and circular. They carry oxygen from the lungs to the muscles and organs.
Nerve cells. They are star-shaped. They transmit nerve impulses from different parts of the body to the brain.
Reproductive cells. They enable us to reproduce. Female reproductive cells are spherical. Male reproductive cells are oval with a long tail.