Feathers of the birds are waterproof due to the oily secretion of

Options

A. Cutaneous gland
B. Preen gland
C. Sudorific gland
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks which gland in birds secretes an oily substance that makes their feathers waterproof.

2. **Identifying the Options:**
The options provided are:
- A) Cutaneous gland
- B) Preen gland
- C) Sudorific gland
- D) None of these

3. **Analyzing Each Option:**
- **A) Cutaneous gland:** This term refers to glands located in the skin, including sebaceous and sweat glands. While these glands produce oils, they are not specifically responsible for the waterproofing of feathers in birds.

- **B) Preen gland:** Also known as the uropygial gland or oil gland, this gland is located near the base of a bird's tail. It secretes an oily substance that birds use to coat their feathers, providing waterproofing and maintaining their brightness.

- **C) Sudorific gland:** These are sweat glands found in mammals and are not relevant to birds. They help with thermoregulation in mammals but do not contribute to feather waterproofing.

- **D) None of these:** This option would imply that none of the glands listed are responsible for the oily secretion, which is incorrect.

4. **Conclusion:**
Based on the analysis, the correct answer is **B) Preen gland**. This gland produces the oily secretion that makes the feathers of birds waterproof.

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