Class 6 Science Chapter 8 MCQ

Generally, in human body radius, ulna, humerus are found in arm but femur is found in thigh or upper leg.

Snail have two sets of muscles in the foot of snail which contract and expand alternately, producing a kind of wave effect.

Snails are “gastropods” which means “belly-footed animals”. The movement of snail is called creeping. In a way, the movement of a snail is similar to that of an earthworm.

Hinge Joint allows the movement of bones in only one direction forward and backwards. In a hinge joint, the movement of bones is restricted to one direction by the shape of the ends of the bones which form the joint. Elbow, knee, knuckles (finger joints) and jaw are examples of hinge joints. And knee joint is also a hinge joint. But shoulder joint is an example of ball and socket joint.

In birds, the backward movement of wings pushes the air in backward direction. This air pushes the wings in the forward direction and makes the bird move forward. Thus, during the downstroke of wings, the air is pushed downward and backwards. The equal and opposite reaction force of air pushes the bird up and forward, and makes it fly.

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

The knee joint is an example of hinge joint. At the knee, the lower end of upper leg bone is in the form of a knob and the upper end of the lower leg bones is in the form of a cup. The knob of upper leg bone fits into the cup of lower leg bone to form a hinge joint at the knee. The ligaments hold the upper leg bone and lower leg bones together at the knee joint.

Shoulder joint and hip joint are the examples of ball and socket joints. In the ball and socket joint, one end of the bone has a round shaped like a ball which fits into a socket in the other bone. A ball and socket joint allows much more movement of bones than any other joints found in the human body.

Cartilage is also found on the ends of bones where they meet one another at a joint. Cartilage is also present between the vertebrae of backbone as cartilage disc.

Here, all the statements are correct. Hence, your answer will be option [D].

Femur, or thighbone, is the largest bone in our body. The head of our femur fits into our hip socket and the bottom end connects to our knee.

Snail is a very slow moving animal with a shell on its back. The foot of snail is large, flat and disc-shaped which is made of strong muscles. It is called muscular food.

There are 206 bones in the human skeleton or human body.

Our skeleton consists of hard bones. However, at some places in the skeleton, there is a material which is not as hard as bones and which can be bent easily. That is called cartilage. Cartilage is a kind of softer and elastic bone which is present in nose, ear and the end of bones where they meet one another at a joint.

Here, all the statements are correct. Hence, your answer will be option [D].

Backbone is made up of 33 small bones placed one over the other.

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are incorrect. Hence, your answer will be option [D].

If we open and close a door, we will find that the door can move only “forwards” and “backwards”. Actually, the door is joined to its frame by a small metal “joints” called “hinge”. These hinges allow the door to move only in one direction, “forwards and backwards”. We can move the lower jaw because the lower jaw is connected to the skull by a movable joint called hinge joint. The hinge joint in lower jaw allows the chewing of food.

Snails are “gastropods” which means “belly footed animals”. The movement of snail is called creeping. Remember, an earthworm, however, moves much faster than a snail.

When we want to bend the arm, the bicep muscles contracts means it become shorter and fatter. The contraction of biceps muscle pulls the lower arm bones due to which the lower arm moves up or bends. Biceps muscles is called flexor muscle because it flexes (bends) the arm.

Snail moves with the help of a large, disc-shaped muscular foot. The whole body of a snail is soft and consists of a head, a foot and a shell. Shell is the outer structure (skeleton) of a snail, but it is not made of bones.

The fin-like flippers worn by underwater divers help to swim easily in water. It mainly helps to keep the balance of the body and to keep direction, while swimming (just as fins in fishes).

Upper jaw and skull joints are immovable or fixed. Bones are held, so tightly together that they cannot move at all. The other options are: Shoulder and Arm is ball and socket joint, Knee and Joint is hinge joint, Lower jaw and Upper jaw is hinge joint.