CBSE-Class 6 - Science - Ch8 - Body Movements

NCERT Chapter Solutions and other Q & A

Bones help in movement
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Q1: Fill in the blanks:

Answer:
(a) Joints of the bones help in the _movement_ of the body.

(b) A combination of bones and cartilages forms the _skeleton_ of the body.

(c) The bones at the elbow are joined by a _hinge_ joint.

(d) The contraction of the _muscle_ pulls the bones during movement.




Q2: Indicate true (T) and false (F) among the following sentences.


Answer:

(a) The movement and locomotion of all animals is exactly the same. (False)
(b) The cartilages are harder than bones. (False)
(c) The finger bones do not have joints. (False)
(d) The fore arm has two bones. (True)
(e) Cockroaches have an outer skeleton. (True)

Q3: Match the items in Column I with one or more items of Column II.

Answer:

Column I	Column II
Upper jaw	is an immovable joint
Fish	have fins on the body have a streamlined body
Ribs	protect the heart
Snail	shows very slow movement
Cockroach	has an outer skeleton can fly in the air

Q4:What is a ball and socket joint?

Answer: A ball and socket joint is a moveable joint. It has a rounded end of one bone fit into the cavity (hollow space) of the other bone. It allows movement in all directions. Example: shoulder joints.

Q5: Which of the skull bones are movable?

Answer: Only the lower jaw in skull bones is movable.

Q6: Why can our elbow not move backwards?

Answer: Elbow joint is an example of hinge joint which allows movement back and forth. Therefore, we cannot move our elbow backwards.

Q7: What are joints?

Answer: The place where two bones meet in a skeleton is called a joint.


Q8: How do animals move from place to place? Fill the table.


Answer:

Animal	Body part used              for moving from               place to place	How does the animal move?
Cow	Legs	Walk
Humans	Legs	Walk
Snake	Whole body	Slther
Bird	Feather	Fly
Insect	Wings, Legs	Fly, Hop
Fish	Fins, Whole Body	Swim

Q9: What are bones made up of?

Answer: Bones are made up of Calcium, Phosphorus, and other minerals.

Q10: What is a skeleton?

Answer: The framework of the body formed by the bones and cartilages is called skeleton.

Q11: What are the functions of skeleton?

Answer:

1. Skeleton provides framework and shape to the body.
2. It protects the internal organs (like heart, lungs, brain etc.) of the body.
3. Bone marrow (present in long bones) produces red blood cells and platelets.
4. It acts as lever and helps in movement and locomotion.

Q12: Name the longest bone in the human body.

Answer: The longest bone in the human body is the thigh bone or femer.  It is about 45cm long.

Q13: Name the smallest bone in the human body.

Answer: Stapes is the smallest bone present inside the ear.

Q14: How many bones usually a human body has?

Answer: Human body has 206 bones.

Q15: Why do doctors use X-Ray images?

Answer: Sometimes when we are hurt, or have an accident, doctors use these X-ray images to find out if there is any injury to the bones. The Xrays show the shapes of the bones in our bodies.

Q16: List some important parts of the skeleton.
Answer: 

1. Skull
2. Ribcage
3. Backbone
4. Pelvic bones
5. Shoulder bones
6. Arms bones and leg bones

Q17: What is a Ribcage? How does it help to our body?

Answer: Ribcage is box like structure which is a part of our skeletal system. It consists of 12 pairs of curved bones called ribs. They join the chest bone and the backbone together to form a box. Ribcage protects the internal organs of the body like heart, lungs.

Q18: What is a skull? What is its function?

Answer: The bony part of head is called skull. The skull is made up of many bones joined together. Only the lower jaw bone is movable. It protects the brain.

Q19: How does human body perform its movement activities?

Answer: Human body perform all these activities with the help of the movements of the bones and muscles.

Q20: Do muscles push and pull both?

Answer: No, muscles can pull only. That;s why to move a bone, a pair of muscles act in opposite directions.

Q21: What is the difference between bone and cartilage?

Answer: Bone is hard and inflexible. E.g. femur (thigh bone). While cartilage is soft and flexible. E.g. Ear and nose bones are actually cartilage.