CBSE Class 6 Science Chapter 8 Body Movements Additional Questions

CBSE Class 6 Science 

Chapter 8: Body Movements

Additional Questions

1. What is ball and socket joint? In which direction in allow movements?
2. What are types of movements in pivotal joints?
3. What is fixed joint? Give en example for this.
4. What is skeleton?
5. How X-ray's useful in treatment of injuries?
6. What is a rib cage?
7. What is cartilage?
8. How the muscles help in the movement of bone?
9. Explain the movement of earthworm in soil.
10. How does earthworm fix parts of its body to the ground?
11. How does the earthworm helps the plants during its movements?
12. Explain the movement of cockroaches
13. How does shape of the fish help its movement?
14. How does the muscles help the fishes to swim in water?
15. What is the role of fins in the movement of fish?
16. Explain the movement of snakes

Answers

1. Ball and socket joint is a joint in which the rounded end of one bone fits into the cavity(hollow space) of the other bone. Ball and socket joint allows movement in all the directions.
2. Pivotal joint allow us to bend our head forward and backward and also allow turning right or left
3. There are some joints, which we cannot move because they are joined together at some joints. Such joints are called fixed joints. The joint between the upper jaw and the rest of the head is an example for fixed joint.
4. All the bones in our body form a framework to give a shape to our body. This framework is called the skeleton.
5. The X-rays show the shapes of the bones in our bodies. Doctors use these X-ray images to find out any possible injuries that might have happened to the bones. 
6. Rib cage join the chest bone and the backbone together to form a box. It gives protection to internal organs like heart, lungs etc
7. Cartilages are the parts of the skeleton that are not as hard as the bones. Cartilages can be bent.
8. Muscles work in pairs. When one of them contracts, the bone is pulled in that direction. The other muscle of the pair relaxes. To move the bone in the opposite direction, the relaxed muscle contracts to pull the bone towards its original position, while the first relaxes. A muscle can only pull. It cannot push. Thus, two muscles have to work together to move a bone.
9. An earthworm does not have bones. It has muscles which help to extend and shorten the body.  During movement, the earthworm first extends the front part of the body, keeping the rear portion fixed to the ground. Then it fixes the front end and releases the rear end. It then shortens the body and pulls the rear end forward. This makes it move forward by a small distance. Repeating such muscle expansions and contractions, the earthworm can move through soil. The body secretes a slimy substance to help the movement.
10. There are large number of tiny bristles projected out under the body of an earthworm. These bristles, which  are connected with muscles  help the earthworm to get a good grip on the ground.
11. The earthworm eats during its movement through the soil and throws away the undigested part of the material that it eats. This is makes the soil fertile and helps the growth of the plants
12. Cockroaches walk and climb as well as fly in the air. They have three pairs of legs. These help in walking. The body is covered with a hard outer skeleton. This outer skeleton is made of different units joined together and that permits movement. There are two pairs of wings attached to the breast. The cockroaches have distinct muscles. the muscles near the legs move the legs for walking. The breast muscles move the wings when the cockroach flies.
13. The head and tail of the fish are smaller than the middle portion of the body. This body shape is called streamlined. Because of this shape water can flow around it easily and allow the fish to move in water.
14. The skeleton of the fish is covered with strong muscles. During swimming, muscles make the front part of the body curve to one side and the tail part swings towards the opposite side and thus fish form a curve. Then, quickly, the body and tail curve to the other side. This makes a jerk and pushes the body forward. A series of such jerks make the fish swim ahead. This is helped by the fins of the tail.
15. Fins help to keep the balance of the body and to keep direction, while swimming.
16. Snakes have a long backbone. They have many thin muscles. They are connected to each other even though they are far from one another. They also interconnect the backbone, ribs and skin. The snake’s body curves into many loops. Each loop of the snake gives it a forward push by pressing against the ground. Since its long body makes many loops and each loop gives it this push, the snake moves forward very fast and not in a straight line.