Exercise

Fill in the blanks:

1. Rocks break up due to ______ weathering.

Ans: physical

2. _______ weathering is a mechanical process.

Ans: physical

3. Microorganisms break down animal and plant remains to form  _______  soil/humus).

Ans: humus

4. _______ soil is rich in humus.

Ans: Top

5. _______ (Lime/Peat) is added to acidic soils to raise the pH.

Ans: lime

6. The method of growing crops on steps in hilly regions is called _______ farming.

Ans: terrace

7. "Reduction or prevention of soil erosion is called soil _______.

Ans: conservation

Tick the correct answer:

1. Which layer of soil determines the type of soil?

(i) Topsoil

(ii) Subsoil

(iii) Parent rock

(iv) Bedrock

Ans: (i)

2. Which of the following does not cause weathering?

(i) Wind

(ii) Water

(iii) Lighting

(iv) Heating and cooling of rocks

Ans: (ii)

3. What are the four main layers in a soil profile?

(i) Minerals, water, humus, and air

(ii) Topsoil, subsoil, pieces of rock, and bedrock

(iii) Loam, sand, silt, and clay

(iv) None

Ans: (ii)

4. The water holding capacity is the highest in

(i) sandy soil

(ii) clayey soil

(iii) loamy soil

(iv) mixture of sand and loam

Ans: (iii)

5. In addition to the rock particles, the soil contains

(i) air and water                              

(ii) water and plants

(iii) minerals, organic matter, air and water

(iv) water, air and plants

Ans: (iii)