Statement (I): The soils in nature rarely exist separately as gravel, sand, silt, clay or organic matter. Statement (II): The classification or grouping of soils is mainly based on one or two index properties of soil.
- ABoth Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
- BBoth Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)Correct
- CStatement (I) is true but Statement (II) is false
- DStatement (I) is false but Statement (II) is true
Solution
Concept
Soil classification systems
Step-by-step solution
1. Natural soils are mixtures (for example silty clay with sand), so Statement I is true. 2. Classification systems use grain size distribution and plasticity (one or two index properties), so Statement II is true. 3. Statement II describes how soils are classified, not why they occur as mixtures, so it is not an explanation of Statement I.
Explanation
Both statements are true. Soil mixtures are the reason a classification system is needed, but the statement on index properties does not explain the natural occurrence of mixtures.
Why the other options are wrong
Option (a) would need II to explain I. Options (c) and (d) deny the truth of one of the statements.
Shortcut
Soils are mixtures; classification uses grain size and plasticity.
Common mistake
Choosing (a) because the statements are related.
Correct answer: B) Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)