SOLUTION

The uppermost layer of the soil is the topsoil and it is the most important layer for the growth of plants as it contains essential nutrients in it.

SOLUTION

Manure contains cow dung and decaying leaves. It is added because it is rich in humus and it makes the soil fertile.

SOLUTION

The sun heats up the rocks. The rain cools them off and the wind blows over them. This is how the small pieces of rocks further break down into smaller pieces. With time, these pieces are rubbed against each other, till they become the tiny particles of soil.

SOLUTION

SOLUTION

Manure is an organic matter which is composed of cow dung and decayed leaves. It is added to soil to make it rich in humus and increase its fertility.

SOLUTION

Sandy soil is a soil found in the deserts and on the seashores. Sand particles are big in size with large air spaces  between these particles. This type of soil cannot hold much water.

SOLUTION

The dead parts of plants and animals, called humus which makes the soil rich and fertile.

SOLUTION

Soil is composed of sand, clay, stones, water and humus.

SOLUTION

The remains of living organisms that died millions of years ago and were pressed deep under layers of rocks are known as fossils.

SOLUTION

Clayey soil is sticky and is mostly used for making pots and toys. Clay particles are very fine. There is no air space between the particles. This soil can hold water.

SOLUTION

The three different types of soil are:

1. sandy soil
2. clayey soil
3. loamy soil

SOLUTION

The following factors are responsible for the formation of soil:

1. rain

2. wind

3. Sun

SOLUTION

The absorbed water flows down to the deeper layers of the soil. Sometimes it gets collected inside the ground to form the water table.

SOLUTION

a. vegetable peels

b. old newspaper

c. plastic bottles

d. metal cans

e. glass bottles

SOLUTION

noise pollution

SOLUTION

a. Asthma and dust allergy

SOLUTION

pollution

SOLUTION

Recently, all public vehicles in Delhi have been converted into CNG vehicles because CNG is a relatively eco-friendly fuel and hence, pollutes the environment at a minimum level.

SOLUTION

Oil spills that pollute the oceans are the causes for the sad condition of these birds.

SOLUTION

Land pollution adversely affects the growth of plants and living organisms.

SOLUTION

The main sources of land pollution are solid waste, reuse from mines, forests and agriculture.

SOLUTION

land pollution

SOLUTION

Noise Pollution

SOLUTION

Five causes of noise pollution:

Loudspeakers’, vehicles, industrial machinery, airplanes and loud music.

SOLUTION

The presence of excessive noise in the atmosphere which may be harmful for the human or animal life, is known as noise pollution.

SOLUTION

a. Bathing an animal in the river

SOLUTION

Sea water gets polluted as a result of oil spills.

SOLUTION

Industrial and household wastes released into the river water, pollute it.

SOLUTION

Air Pollution

SOLUTION

The smoke from industries and vehicles contaminates the air.

SOLUTION

Air Pollution, Noise Pollution, Water Pollution, Land Pollution.

SOLUTION

The mixing of harmful gases and other particles in the air is called air pollution.

SOLUTION

a.True

b.False

c.True

d.True

e.True

SOLUTION

Perfume is a pleasant smelling liquid.

SOLUTION

Water, oil, kerosene, petrol etc are some examples of liquids which we use.

SOLUTION

1)   Gases do not have a fixed volume.

2)   They are not visible.

3)   They can flow more easily than liquids.

4)   We cannot hold them in our hands.

SOLUTION

The process by which a liquid changes into a solid is called freezing.

SOLUTION

The process by which water vapour changes into water is called condensation.

SOLUTION

Air, compressed natural gas etc are some examples of gas.

SOLUTION

A liquid takes the shape of the container holding it, as it does not have a shape of its own. Liquids can flow easily from one container to another.

SOLUTION

Water exists in all the three phases:

Solid ice, liquid water and gaseous vapours

SOLUTION

The process by which water changes into water vapour or steam at a particular temperature of 100 degree celsius is called boiling.

SOLUTION

Solids are usually hard and have a definite shape and size.

SOLUTION

Wood, ice, sand, glass etc are some of the commonly known solids.

SOLUTION

In solids, particles are closely packed, so there is very little space between them.

In liquids, particles are not as closely packed as in solids. They are free to move.

Gases do not have a fixed shape because the particles are very loosely packed.

SOLUTION

Solid, liquid and gases are the three states of matter.

SOLUTION

Anything that has mass and occupies space is called matter.

SOLUTION

We must breathe in fresh and clean air. It is important for good health. Plants keep the air fresh and clean, so we should grow plants in our surroundings.

SOLUTION

Answers may vary.

SOLUTION

1. Drinking with a straw
2. Sailing in boat
3. Windmills
4. Flying a paper airplane.

SOLUTION

Answers may vary

SOLUTION

1. Air is invisible, we cannot see it.
2. It has no taste and no smell. But we can feel it when it moves.
3. It can be heated or cooled.
4. It exerts pressure. This because air has weight.
5. It fills space.

SOLUTION

Air pollution is caused by harmful gases like carbon dioxide, carbon monoxide, nitrous oxide and so on. These are called air pollutants.

SOLUTION

asthma

SOLUTION

The harmful effects of air pollution are:

1. asthma

2. dust allergy

3. skin irritation

SOLUTION

In urban areas, the cases of dust allergy and asthma are increasing day by day because the cities are suffering from excessive air pollution.

SOLUTION

The three causes are:

1. Smoke from factories

2. Burning of forests

3. Burning of plastics

Answers may vary.

SOLUTION

a. Bursting of crackers b. Dust from construction sites

SOLUTION

Yes, the burning of fossil fuel like coal leads to air pollution.

SOLUTION

The image depicts air pollution through burning of fossil fuel like petrol.

SOLUTION

Agree

SOLUTION

a. Air Pollution

b. Soil Pollution

c. Water Pollution

d. Noise Pollution

SOLUTION

SOLUTION

Answers may vary.

SOLUTION

5 June

SOLUTION

Disagree

SOLUTION

SOLUTION

True

SOLUTION

Agree

SOLUTION

The three ways are:

1. Reducing the amount of household garbage.

2. Planting more trees.

3. Not playing loud music.

Answers may vary.

SOLUTION

The farmer is spreading insecticides on the crops and insecticides pollute the soil.

SOLUTION

SOLUTION

asthma, dust allergy, deafness, headache, stress

SOLUTION

The telephone is one of the biggest forms of communication in today’s time.

SOLUTION

The kings in early days sent their personal agents to carry their letters all the way from one state to the other. The agents delivered the message by walking or by riding a horse which took them months to deliver the message.

SOLUTION

It was banned so that cruelty towards pigeons could be avoided.

SOLUTION

No, not in India. The use of pigeons as messengers was banned in 1948.

SOLUTION

Ami pierced through the war stricken sky very bravely and delivered the message to the French Army and saved the precious lives.

SOLUTION

The head of the group released his last messenger pigeon Cher Ami to carry their message to the French army.

SOLUTION

Once, during the First World War, a group of French soldiers got trapped on the side of a hill, surrounded by enemy soldiers. There was a little chance of their survival as their own army was bombarding them unknowingly.

SOLUTION

Smartphone

SOLUTION

It means dear friend in French.

SOLUTION

The person who receives a letter, is the receiver of the letter.

SOLUTION

The person, who writes a letter and mails it, is the sender.