Question

Arrange the given events (i - iv) in the process of weathering in the correct order of their occurrence.

i) Rainwater enters the cracks and becomes ice when the temperature drops.
ii) Ice or roots of plants widen the cracks.
iii) Rocks exposed to temperature changes undergo expansion and contraction.
iv) Over a period of time the rocks break and disintegrate into many pieces.

• A. i→ ii→iii→iv
• B. i→iii→ii→iv
• C. ii→i→iii→iv
• D. iii→i→ii→iv

Answer 1

The correct option is D iii→i→ii→iv

An ecosystem includes living organisms (biotic factors) along with the physical environment (abiotic factors) with which they interact. For example, living (fishes, frogs) and nonliving things (soil, temperature) in a pond ecosystem. Soil is an important abiotic factor.

Soil formation starts with the breakdown or dissolving of rocks and minerals, also called as weathering of rocks. Nature (texture) and properties of soil vary in different places and the major reasons for this are climate, weathering, types of rocks and soil development process. Exampley include clay (lumpy and is sticky when wet and rock hard when dry), sandy (It drains easily, dries out fast) etc.

Weathering can be physical, chemical and biological. The given events represent one of the many ways in which rocks can be weathered to form soil. It involves the impact of both physical and biological factors on the process of weathering.

Rocks exposed to temperature changes, undergo expansions (with heat), contractions (with cold) and start cracking over time.
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Rainwater enters these cracks and becomes ice when the temperature drops.
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The ice widens the cracks further. Sometimes the roots of plants also cause cracks in the rocks.
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Slowly, over a period of time, the rocks break and disintegrate into many pieces.

Figure : Weathering