Question

The breakdown of detritus into smaller particles by earthworm is a process called
A. Humification
B. Fragmentation
C. Mineralization
D. Catabolism

Answer 1

Detritus simply means small rock particles and organic waste material in the ecosystem. It provides essential value for the ecosystem. It provides nutrients which are important for the growth of plants and it is broken down into smaller particles by various organisms such as earthworms.

Complete answer:
Detritus is small rock particles and organic waste matter such as dead plants, dead remains of animals, fecal matter present in the ecosystem. It is the raw material for decomposition and is essential for the growth of plants.
Decomposition is a process by which organic matter is broken down into simpler particles. There are 5 distinct steps of decomposition including fragmentation, leaching, catabolism, humification and mineralization.
Earthworms contribute to decomposition by fragmentation of detritus. They are generally called detritivores. Earthworms are called ecosystem engineers. They deliver plant derived carbon deeper into the soil.
Leaching is the process by which water soluble substances such as fertilizers or pesticides are washed out from soil.
Catabolism is the process of breaking down complex particles into simpler form. It is carried out by microorganisms such as fungi and bacteria.
Humification is the process of formation of a dark colored layer called humus. It is highly resistant to the action of microbes and hence cannot be easily decomposed. Humus is very rich in nutrients and provides fertility to the soil.
Mineralization is the process by which humus is degraded to release inorganic nutrients. It is also the final step.
Decomposition is affected by a myriad of factors including temperature, moisture, soil pH, inorganic chemicals, aeration etc.

Therefore, the correct answer to this question will be option ‘B’- fragmentation.

Note: In context with the above provided information, earthworms not only help in fragmentation but also helps in enhancing the quality of soil. They are one of the most significant soil organisms and widely beneficial for agricultural farming.