- The skeleton comprises of the skull, backbone, ribs, breastbone, shoulder, hip bones and the bones of hands and legs.
- Bone and cartilage form the skeleton of the human body. It gives support and shape to the body and helps in movement. It also protects the inner organs.
- Cartilage is the additional part of our skeleton.
They are not as hard as bones but strong and flexible. Cartilage is present in the outer part of ear, nose tip, etc.
- A joint is the place where two or more bones meet (articulate).
- There are four kinds of joints in our body. They are ball and socket joint, pivot joint, hinge joint and immovable joints.
- The act of moving from place to place is known as locomotion. It involves the movement of the whole body, as in walking, running, swimming or flying.
- Body movements are helped by muscular contractions and relaxations.
- Birds fly with the help of wings, strong muscles and light (hollow) bones.
- Fish swim by forming loops alternately on two sides of the body with the help of the tail fin.
- An earthworm moves with the help of its muscles. The contraction and expansion of muscles helps the earthworm to move.
- A snail has a muscular foot which helps it to move.
- A cockroach has three pairs of legs which help it to walk and move. It has two pairs of wings which help it to fly.
- Snakes have a long back bone and many thin muscles. While moving a snake curves into many loops. Each loop gives it a forward push by pressing against the ground.