• The body of a living organism is made of cells.
• A cell is considered as the basic unit of all organisms.
• Depending on the number of cells they consist, organisms can be unicellular or multicellular.
• Living things show structural organization, that is, the bodies of multicellular organisms have the following organization.
• There are different organ systems present in our body:
1. Respiratory system
2. Circulatory system
3. Digestive system
4. Nervous system
5. Skeletal system
6. Muscular system
7. Reproductive system
8. Excretory system
• Each system performs a set of important functions.
• The skeletal system along with the muscular system helps in movement.
• Movement is a function unique to animals.