Page 68 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

2. What do you mean by soil profile?

Ans. The vertical section through soil showing its different layers is called the soil profile.

Each layer differs in feel (texture), colour, depth and chemical composition. These
layers are referred to as horizons.

3. Name the soil with highest water-absorption rate.

Ans. Sandy soil has the highest water absorption rate.
4. List down the climatic factors which affect the soil profile.

Ans. The climatic factors that affect the soil profile include :

• Temperature • Precipitation
• Wind • Humidity

• Seasonal variations

5. Write the composition of soil.
Ans. Soil composition is a mixture of soil ingredients that varies from place to place. It is

composed of both biotic and abiotic materials such as air, water, minerals, plants and

animal matter.

6. Define percolation.
Ans. Percolation can be defined as the property of the soil by which it allows water to flow

through it.

7. What do you mean by exfoliation?
Ans. In the day time, due to extreme heat of the Sun, rocks expand from outside but

remain cool from the inside. At night, the temperature drops due to which rocks

cool down and contract. This continuous cycle of uneven expansion and contraction
breaks them. This process is known as exfoliation.

8. What do you mean soil pollution?

Ans. When soil gets contaminated and its quality deteriorates, it is known as soil pollution.

It occurs when the pollutants, that cause pollution, reduce the quality of the soil
and there is a high-level presence of man-made chemicals and other non-desirable

substances.

9. What is weathering?
Ans. Weathering is the process by which rocks on the land surface break down or crumble

because of the action of the elements of weather, such as rain, frost and temperature

changes. It plays a key role in the process of soil formation. This is a continuous and
an ongoing process.

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