Question

The soil near the surface is usually darker than about one meter down, this is because the top soil:

• A. Is richer in calcium and magnesium
• B. Contains more organic matter
• C. Is wetter than the sub-soil
• D. Is drier than the sub-soil

Answer 1

Answer: (B)

Contains more organic matter

The uppermost layer of soil is usually darker in colour due to the presence of huge amount of organic matter. Organic matter is composed of roots, dead leaves, insects, small organisms and animals which eventually get degraded to form humus and make the soil fertile. Humus is black in colour due to the large quantity of carbon.

So, the correct option is 'B'.