Lanugo is

Options

A. Feather as junction of rachis and quil
B. A certain feather present on tail region
C. Coating of hair on epidermin of man
D. A coating of fine hair with which the body of mammals is covered during foetal development.

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "Lanugo":**
- Lanugo is a term derived from the Latin word "lana," which means wool. It refers to a specific type of hair.

2. **Identifying the Context:**
- Lanugo is associated with fetal development. It is the initial hair produced by the fetus while it is still in the mother's womb.

3. **Timing of Appearance:**
- This fine hair begins to appear around the 16th week of gestation.

4. **Characteristics of Lanugo:**
- Lanugo consists of very fine, soft hair that is typically unpigmented (colorless).

5. **Duration of Presence:**
- Lanugo usually falls off a few weeks after birth, indicating that it is temporary.

6. **Evaluating the Options:**
- Option A: "Feather as junction of fraches and quill" - Incorrect, as this refers to bird anatomy, not human hair.
- Option B: "A certain feather present on the tail region" - Incorrect, as this again refers to feathers, not hair.
- Option C: "Coating of hair on epidermis of man" - Incorrect, as this does not specifically refer to lanugo.
- Option D: "A coating of fine hair with which the body of mammals is covered during fetal development" - Correct, as this accurately describes lanugo.

7. **Conclusion:**
- The correct answer is Option D, which defines lanugo as a coating of fine hair present on the body of mammals during fetal development.

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