Explanation:

Vermicomposting is the process of using worms, particularly earthworms, to break down organic waste material (such as food scraps, leaves, and manure) into nutrient-rich compost. The worms ingest the organic matter and excrete it in the form of castings, which are rich in nutrients and help improve soil fertility.

Here's why the other options are incorrect:

• (A) Fungus: Fungi are important in decomposing organic matter, but they are not the primary agents in vermicomposting.
• (C) Bacteria: Bacteria also play a role in decomposition, but they are not specifically responsible for vermicomposting.
• (D) Birds: Birds do not contribute to vermicomposting; they may help with waste reduction in other ways but not through the process of decomposition in vermicomposting.

Thus, worms are the key players in vermicomposting, making (B) Worms the correct answer.