Correct Option
The correct option is 1 and 3 only.
Explanation
Exogenic geomorphic processes are geological phenomena that originate at or near the Earth's surface. They are primarily driven by energy from the sun and gradients created by tectonic factors. Climate is the most significant factor influencing these processes, as it dictates the intensity and type of weathering, mass wasting, erosion, and deposition.
Statement-wise Analysis
- Statement 1 is Correct: Exogenic geomorphic processes vary significantly from region to region. This variation is largely due to differences in thermal gradients created by latitudinal, seasonal, and land-sea variations in solar energy receipt. These thermal gradients, along with precipitation patterns, determine the type and intensity of geomorphic agents (wind, water, ice) active in a region.
- Statement 2 is Incorrect: The depth of the weathering mantle (the layer of weathered rock and soil) is not uniform across different climatic regimes. It is strongly controlled by temperature and precipitation. For instance, the weathering mantle is typically deepest in hot and humid tropical regions due to intense chemical weathering, whereas it is shallow or negligible in arid deserts and polar regions where physical weathering dominates but chemical action is limited.
- Statement 3 is Correct: Vegetation distribution is primarily determined by climatic factors such as precipitation and temperature. Vegetation exerts an indirect influence on exogenic processes. For example, dense vegetation binds the soil, reducing erosion by running water and wind, while root systems can contribute to physical weathering (root wedging) and chemical weathering (release of organic acids).
Key Takeaway
Key Takeaway: Climate is the primary regulator of exogenic geomorphic processes. The intensity of weathering and the depth of the weathering mantle vary directly with climatic zones, being maximal in hot, humid regions and minimal in cold or dry regions.