Choose the correct answers to the questions from the given options:

1. Which of the following factors does NOT directly influence soil formation?
   1. Type of parent material or bedrock
   2. Climatic features such as temperature and rainfall
   3. Presence of living organisms
   4. Proximity to the ocean
2. How does surface relief or topography affect soil formation?
   1. By determining the type of bedrock
   2. By influencing drainage patterns
   3. By altering the chemical composition of soil
   4. By increasing the number of living organisms
3. Which type of alluvium is predominantly found in the mouth of the Ganga-Brahmaputra Rivers?
   1. Coastal alluvium
   2. Deltaic alluvium
   3. Inland alluvium
   4. Sandy alluvium
4. What is a key distinguishable feature of inland alluvium compared to deltaic alluvium?
   1. Inland alluvium is more compact.
   2. Inland alluvium is clayey and finer in texture.
   3. Inland alluvium is porous and sandy.
   4. Inland alluvium is found at the river mouth.
5. What is the primary origin of black soil or regur?
   1. Laterite rocks
   2. Erosion of limestone
   3. From the disintegration of lava rocks
   4. Sedimentary deposits from rivers
6. Why is black colour soil known as self-ploughing soil?
   1. It requires no normal ploughing due to its softness.
   2. It naturally forms deep cracks when dry, allowing air, sunlight and water to seep through.
   3. It is automatically fertilised by natural processes.
   4. It is easy to cultivate with modern machinery.
7. What is the primary reason for the red colour of red soil?
   1. High clay content
   2. High iron oxide content
   3. High organic matter
   4. Abundance of magnesium
8. Why is red soil generally considered infertile?
   1. It has high sand content.
   2. It is deficient in nitrogen, lime, phosphoric acid and humus.
   3. It is not suitable for any type of vegetation.
   4. It has a low water retention capacity.
9. The causes of desertification are
   1. over grazing
   2. deforestation
   3. over cultivation
   4. all of these
10. The conditions that lead to the formation of laterite soil are:
    1. high temperature and heavy rainfall.
    2. low temperature and heavy rainfall.
    3. low temperature and low rainfall.
    4. high temperature and low rainfall.

Define soil. Why is it considered an important resource?

State three factors that influence soil formation.

What do we understand by soil profile? Name the typical horizons that constitute the soil profile.

What is humus? Why is it an important constituent of soil?