EVERYDAY SCIENCE

Detailed explanation-1: -Humus is dark, organic material that forms in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up. This material is called leaf litter.

Detailed explanation-2: -The topsoil layer is a mixture of sand, silt, clay and broken down organic matter, called humus. Humus is rich, highly decomposed organic matter mostly made from dead plants, crunched-up leaves, dead insects and twigs. Topsoil is the home of living things and the materials that they make or they change.

Detailed explanation-3: -Humus is the dead and decaying bits of animals and plants present in the topmost layer of soil.

Detailed explanation-4: -It contains more organic material than the subsoil and so it is darker in color. Humus is the decayed remains of the plants and animals, which breaks down in thesoil by the microbes. Therefore, this happens more in the topsoil, than in any other soil layer. Thus, the top layer of soil has more humus than other layers.

Detailed explanation-5: -The correct option is B Top soil. The uppermost layer of the soil is called topsoil and this layer contains humus, plant roots, and living creatures.