Class 6 Science Chapter 5 MCQ

Snakes do not have legs, even then they move quite fast because a snake moves forward by moving its body sideways in the form of many loops and pushing against the ground.

When the fish’s tail moves side to side, it pushes the water sideways as well as back-wards. The backward push of tail on water, makes the fish move forward.

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].

In the human body the upper arm consists of a single bone called humerus. The lower arm or forearm is from elbow to wrist. The lower arm or forearm is made up of two bones radius and ulna. The upper arm bone is connected to the lower arm bones by a hinge joint at the elbow.

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.

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

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.

The bony framework inside our body is called a skeleton. In human beings, the skeleton is inside the body, so it is called an endoskeleton. Actually, our body is supported on a hard framework of bones. We can stand straight because of the “Internal skeleton”.

The lower arm is made up of two bones as radius and ulna.

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.

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

The pivot joint allows rotation around an axis. A pivot joint exist between our skull and the top vertebra of backbone. Another pivot joint occurs in the forearm or lower arm near the elbow. The pivot joint in the forearm make us turn our forearm to hold the palm of hand up or down.

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

Birds can fly because their bodies are adapted or modified for flying purposes. As their flight feathers provide a large flat surface which is light but strong. Their bones are hollow and light. And their bodies are streamline and extremely light. Birds have breast bone which is extended for the attachment of large flight muscles (which moves the wings up and down).

Snake moves forward by moving its body sideways in the form of many loops, and pushing against the ground. The special name of the wave like motion of the snake is called “slither”. And also remember, snake does not move in a straight line because the sideways pushes of the loops push the snake forward as well as sideways.

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.

Two muscles (a pair) work together to move a bone. When one muscles of the pair contracts, then the other muscles of the pair is relaxed. The alternate contraction and stretching brings about the movement.

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).

Snail does not have both muscles and skeleton for movement. The shell serves for muscles attachment and protection. The movement is carried out only with the help of large disc-shaped muscular foot that has two sets of muscles. In earthworm, a hydrostatic skeleton (fluid filled cavity surrounded by muscles) is present. The alternate contraction and relaxation of muscles and pressure of the fluid helps in burrowing. Dog and human beings have Musculo-skeletal system for movement.

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.