Correct Option
The correct option is 1 and 4 only
Explanation
Soil formation (pedogenesis) is influenced by five major factors: parent material, relief (topography), climate, biological activity (organisms), and time. Each factor plays a distinct role in determining the physical and chemical properties of the soil.
Statement-wise Analysis
- Pair 1 is Correct: Parent Rock (or parent material) is the passive control factor in soil formation. It determines the soil's fundamental properties, including colour, texture, chemical properties, mineral content, and permeability.
- Pair 2 is Incorrect: Climate is the most active factor in soil formation. Temperature and precipitation primarily influence the rate of weathering and the formation of humus. The accumulation of soil is primarily determined by Relief (topography), as steep slopes lead to erosion while flat areas allow for deposition.
- Pair 3 is Incorrect: Relief (altitude and slope) determines the accumulation of soil and the exposure to the sun. The rate of humus formation is primarily determined by Climate (specifically temperature and moisture), which regulates bacterial activity and the decomposition of organic matter.
- Pair 4 is Correct: Time is the factor that determines the maturity of the soil. Over a longer period, soil forming processes act more extensively, determining the thickness of the soil profile. Older soils generally have well-developed horizons compared to younger soils.
Key Takeaway
Parent Rock defines the chemical and physical basics (colour, texture); Climate drives the rate of weathering and humus formation; Relief dictates soil depth and accumulation; and Time determines the maturity and thickness of the soil profile.