Which stage of silkworm secretes silk?
(a) Adult
(b) Pupa
(c) Cocoon
(d) Larva

Options

A. Adult
B. Pupa
C. Cocoon
D. Larva.

Answer

To determine which stage of the silkworm secretes silk, let's analyze the life cycle of the silkworm, scientifically known as Bombyx mori.

### Step-by-Step Solution:

1. **Understanding the Life Cycle**: The life cycle of the silkworm includes several stages: egg, larva (caterpillar), pupa (cocoon), and adult moth.

2. **Identifying the Silk-Secreting Stage**: The silk is produced during the pupation stage. Specifically, the larva (caterpillar) undergoes a transformation into a pupa, during which it secretes silk.

3. **Role of Salivary Glands**: The silk is secreted from the salivary glands of the silkworm. When the larva enters the pupation stage, these glands produce a sticky fluid that hardens into silk when it comes into contact with air.

4. **Conclusion**: The correct answer to the question is that the silk is secreted during the larval stage as it transitions into the pupa stage.

### Final Answer:
**(d) Larva**

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