Q. The term “eluviation and illuviation” are associated with which of the following?

[A] Soil formation

[B] Continent building

[C] Deep sea plains

[D] Atmospheric circulation

Answer: A

Explanation: Climate is an important active factor in soil formation. The climatic elements involved in soil development are:

  1. Moisture in terms of its intensity, frequency and duration of precipitation – evaporation and humidity;
  2. Temperature in terms of seasonal and diurnal variations.

Precipitation gives soil its moisture content which makes the chemical and biological activities possible.

  • Excess water helps in the downward transportation of soil components through the soil (eluviation) and deposits the same down below (illuviation).

Source: NCERT – Fundamental of Physical Geography