The correct option is 1 only
Explanation
Soil formation, or pedogenesis, is driven by the interaction of five major factors: parent material, topography, climate, biological activity, and time. These factors are classified into active factors (climate and organisms) and passive factors (parent material, topography, and time).
Statement-wise Analysis
- Statement 1 is Correct: Parent material is considered a passive control factor in soil formation. It provides the basic mineral matter and structural framework upon which active factors, such as climate and biological agents, act to develop soil profiles.
- Statement 2 is Incorrect: Parent material is not restricted to in-situ weathered rock debris. It can be in-situ (residual soils remaining over the bedrock) or transported deposits (transported soils moved by agents like water, wind, ice, or gravity).
- Statement 3 is Incorrect: It is factually incorrect to state that dissimilar bedrocks always produce dissimilar soils. While parent material heavily influences young soils, over long periods, climate becomes the dominant factor. Under the same intense climatic conditions, soils formed from different bedrocks may eventually develop similar characteristics (convergent evolution). Conversely, the same bedrock can produce different soils under different climates.
Key Takeaway:
Parent material determines the initial chemical composition and texture of the soil but is a passive factor. It comprises both residual (in-situ) weathered rock and transported sediments.