Weathering and Soil Formation Quiz - ICSE Class 8 Geography
Free practice quiz: Weathering and Soil Formation (ICSE Class 8 Geography). 50 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which type of weathering involves the breakdown of rocks by living organisms?
- Physical weathering
- Chemical weathering
- Biological weathering
- Mechanical weathering
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Answer: C. Biological weathering
Biological weathering is the decomposition of rocks and minerals by plants, animals, and microbes. This can occur through roots growing into cracks, burrowing animals, or the secretion of acids by microorganisms.
Soil formation is a slow process that can take hundreds to thousands of years. The original rock material from which soil develops is called the:
- Regolith
- Parent material
- Subsoil
- Humus
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Answer: B. Parent material
The parent material is the underlying bedrock or unconsolidated sediment from which soil develops. Its composition and characteristics directly influence the properties of the resulting soil.
Differential weathering refers to the process where:
- All rocks weather at the same rate
- Different rocks weather at different rates due to variations in their composition and structure
- Weathering only occurs on exposed rock surfaces
- Weathering is solely determined by climate
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Answer: B. Different rocks weather at different rates due to variations in their composition and structure
Differential weathering is the process by which rocks of varying mineral composition and structure break down at different rates when exposed to the same weathering environment. This leads to uneven erosion and the formation of varied landforms.
The formation of sinkholes is a classic example of landform development due to:
- Physical weathering by frost wedging
- Chemical weathering of limestone by carbonation
- Biological weathering by plant roots
- Abrasion by glacial ice
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Answer: B. Chemical weathering of limestone by carbonation
Sinkholes are typically formed in areas with soluble bedrock, primarily limestone. Carbonic acid in rainwater dissolves the limestone, creating underground cavities. When the roof of these cavities collapses, sinkholes are formed.
The formation of a porous and spongy texture in rocks due to the weathering of feldspar and mica is often a result of:
- Abrasion
- Oxidation
- Hydrolysis
- Frost wedging
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Answer: C. Hydrolysis
Hydrolysis breaks down silicate minerals like feldspar and mica, often transforming them into clay minerals. This process can weaken the rock structure, making it more porous and crumbly.