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(a) vertebrae

(a) Movable joint and 

(b) Immovable joint

Lower end is attached to radius ulna and upper end is attached to pectoral girdle.

There are five bones in palm. Our fingers and thumb also have bones which is called carpals and thumb bones respectively. Each bone has three bones and thumb has two.

1. Skeleton

2. 33 

3. Shaft 

4. Seven 

5. Muscles

No, they can move in a single direction.

Ahard and strong bone is felt. This bone is humerus.

1. Humerus 

2. Radius Ulna 

3. Carpals, 

4. Metacarpal 

5. Phalanges.

The number of bones in our one hand is 30.

Humerus is called Shaft

Number of bones in thumb of hand 2

(b) hinge joint

(c) bone of hand

1. five 

2. Pectoral girdle 

3. three 

4. contraction, expansion (relaxation).

Vertebral column.

Back bone is formed by 33 small vertebrae.

There are two types of joints.

Longest bone of our body is femur.

1. preservation of food 

2. acidus 

3. bitter 

4. CaO 

5. alkaline substance

6. indicator 

7. deep pink or deep red

1. organ 

2. skull 

3. Excretion 

4. skin 

5. hormones

(a) shoulder

Radius and ulna are two bones of wrist of our hand. The first one towards the outside of arm and second one towards the inside the arm are respectively called radius and ulna. The end towards the elbow of this bone is attached to humerus and its lower end to wrist bones.

1. preservation of food 

2. acidus 

3. bitter 

4. CaO 

5. alkaline substance 

6. indicator 

7. deep pink or deep red

Correct answer is (c) Digestion

We are able to bend or rotate our body in places where two parts of our body seem to be joined together – like elbow, shoulder or neck. These places are called joints. If ft our body has no joints, it would not be possible for us to move in any way at all.

Bones cannot be bent. But we can bend our elbow. It is not one long bone from ft the upper arm to our wrist. It is different bones joined together at the elbow. Similarly, there are many bones present in each part of the body.

We can bend or move our body only at those points where bones meet. There are different types of joints in our body to help us carry out different movements and activities. Let us see the function / movements of some of the joints in our body.

Fixed joints which do not allow movement are called fixed joint.

Gliding joints allow only a limited amount of movement of sliding nature of cartilage. For example, the joints of back bone.

Hinge joint allows movement only in one plane. For example, fingers, knees. Elbow joint is composed of hinge joint. These joints allow movement in one plane and up to 180° only. Hence, we cannot move our elbows backwards.

Piyotal joint allows movement in all planes, i.e. up and down, side and other planes. For example, head.

Ball and socket joint allows movement in all directions. The rounded end of one bone fits into the cavity (hollow space) of other bone. Such a joint only allows movements in all directions. For example, joint between upper arm.

1. True.

2. False

Correct statement: Acids are sour in taste. Bases are bitter in taste.

3. False

Correct statement: Bases are soapy to touch only in aqueous media, not in dry nature.

4. True

5. False

Correct statement: All alkalis are base, but all bases are not alkalis.

Shoulder bone is called pectoral girdle. Pectoral girdle is the set of bones in the perpendicular skeleton which connects to the arm on each side. The pelvic girdle (hip girdle) is formed by a single bone, the hip bone or coxal bone (coxal = “hip”), which serves as the attachment point for each lower limb. These two girdles are basis of our skeleton

Normally, the entry of food into the windpipe is prevented by a flap like structure called Epiglottis. But when we eat in a hurry, the flab gets lesser time to close the windpipe. Thus some of the food particles enter into the windpipe. It creates a hindrance in the movement of air in the windpipe and results in coughing or hiccup.

A substance which contains one or more replaceable hydrogen atoms.

1. Sweating plays an important health role as it helps to maintain constant body temperature by cooling us down. 

2. When it is hot and we sweat that moisture evaporates and cools us immediately. 

3. This is why we sweat more when the summer is very hot.

1. Acids are sour in taste. 

2. They are corrosive in nature. Strong acids can spoil substances like human skin, clothes and paper. 

3. Generally acids exist in liquid state but few acids exist in solid state too.

E.g. Benzoic acid. 

4. Acids are colourless. 

5. Acids change the colour of the indicators. Blue litmus paper turns red and methyl orange turns pink when treated with acids.

The oxygenated and deoxygenated blood are separately circulated. So the heart is divided into two halves by a thick muscular wall.

1. They are corrosive in nature. 

2. They undergo ionization in aqueous solution. 

3. They conduct electricity in aqueous solution. 

4. They undergo neutralization reaction.

An indicator or acid – base indicator is a chemical substance which indicates the acidic or basic nature of a solution by suitable colour change.

(a) an indicator

Difference between acids and bases: 

Acids: 

1. They produce H ions in water. 

2. They are sour in taste. 

3. Few acids are in solid state.

4. Acids turn blue litmus paper red. 

Bases: 

1. They produce OH^- ions in water. 

2. They are bitter in taste. 

3. Most of the bases are in solid state. 

4. Bases turn red litmus paper blue.

No, acids and bases are corrosive in nature.

When acids and bases are mixed in definite proportions they give a neutral solution.

1. We have seen in the process of neutralization, both the acidic and the basic qualities are destroyed. 

2. Actually when an acid and a base are mixed, a chemical reaction takes place and salts are produced. 

3. For example by neutralizing Hydrochloric acid solution with Caustic soda (Sodium Hydroxide) solution, a salt Sodium Chloride is produced. 

4. Production of salt depends on the quantity of acid and base by proportion in a very specific manner.

1. Potassium hydroxide is used to make bathing soaps.

2. Sodium hydroxide is used to make washing soaps. 

3. Sodium hydroxide is also used in paper industries, textile industries and in the preparation of medicines. 

4. Calcium hydroxide is used for white washing. 

5. Aluminum hydroxide and magnesium hydroxides are used in antacids to cure acidity problems. 

6. Ammonium hydroxide is used to manufacture fertilizers, nylon, plastics and rubber.

By restriction enzyme bacteria can attack and destroy the phage DNA in case of viral attack and thereby prevent viral attack.

Neurons are specialised nerve cells for transmission of impulses.

These cells have following adaptations to serve this function:

1. they are extremely long to transmit impulses.

2. they have a myelin sheath to help elctric impulses to pass along the cell.

3. they have nerve endings called dendrites which help in transmitting the impulse throughout the length of the cell.

4. cyton or cell body has projections to receive impulses.

5. end of nerve cells form 'synpase'.