Question

(b) Name four kinds of freely movable joints.
(a) Define floating ribs.
(c) Define bone marrow.
(d) Why is mucous secreted by a snail's foot?
(e) What is the function of a bone marrow?​

Answer 1

Answer:

Joints

The location where two or more bones meet is called a joint. Ligaments bind a bone to another bone. Tendons bind a bone to a muscle.

Types of Joints

Fixed joints: The joints where no movement of bones is possible are called fixed joint. The joints in the skull bone (cranium) are examples of fixed or immovable joints.

Moveable joint: Movement is possible in these joints. There are two types of movable joints:

Freely movable joints and

Partially movable joints.

There are four types of movable joints in the body; which are as follows:

Ball and socket joint: In this joint the rounded end of one bone fits into the cavity (hollow space) of another bone. It permits movement in all directions. The joints between shoulder and the upper arm is an example of ball and socket joint. Similarly, the joint between thigh and hip is an example of ball and socket joint.

Pivot Joint: This type of joint allows movements in many planes, viz. up and down, side to side movements. The joint between the skull and the vertebral column is an example of pivot joint.

Hinge joint: This joint is similar to the hinges in a door. This joint allows movement only in one plane and only up to 1800. The knee joint and elbow joint are examples of hinge joint.

Gliding joints: The movement in this joint happens due to sliding of bones over one another. Joints between the rings of the backbone are examples of gliding joint. The wrist joint is also an example of gliding joint.

Answer 2

Hey mate!!!!!

Here is your answer

b) four kinds of freely movable joints are

1. Ball and socket joint
2. Hinge joint
3. pivot joint
4. gliding joint

a) Any of the lower ribs which are not attacted directly to the brestbone.

c) A spongy substance found in the center of the bones is called bone marrow.

Umm I think in the question "d" you have written a spelling mistake. You have written "mucous" in the place of "mucus" Hmm anyways here is your answer.

d) snail produce slime which is a type of mucus, which is produced from a special gland found in the snails foot. The purpose of the slime is to enable the snails to move.

e) bone marrow manufactures bones marrow stem cells and other substances , which in turn produce blood cells. Each type of blood cells is made by the bone marrow and has an important job.

Hope that this will help you

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