The correct option is D.
Explanation
The process of converting biodegradable organic waste into high-quality manure using specific species of earthworms is known as vermicomposting. Redworms (Eisenia fetida) are the most commonly utilized species for this purpose due to their high consumption rate and efficiency in breaking down organic matter.
- Statement A is Incorrect: The physical appearance or opacity of redworms is irrelevant to the biochemical process of decomposition or the quality of the food they consume.
- Statement B is Incorrect: Tensile strength is a mechanical property of materials and does not pertain to the biological functions or the composting efficiency of redworms.
- Statement C is Incorrect: Redworms are living biological organisms and are inherently biodegradable. This statement does not describe their functional role in waste management.
- Statement D is Correct: Redworms possess a specialized structure called a gizzard, which helps them grind food particles. As they ingest organic waste, it passes through their digestive system where it is broken down by enzymes and microbes. The excreted cast (vermicompost) is a nutrient-rich humus that significantly enhances soil fertility.
Redworms act as biological catalysts in vermicomposting, accelerating the decomposition of organic waste into nutrient-dense manure through ingestion and digestion.