•    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.