Root hairs are
(a) always unicellular
(b) sometimes unicellular
(c) sometimes multicellular
(d) always multicellular

Options

A. always unicellular
B. sometimes unicellular
C. sometimes multicellular
D. always multicellular.

Answer

**Step-by-Step Solution:**

1. **Understanding Root Hairs**:
- Root hairs are specialized structures that emerge from the roots of plants. They are tubular outgrowths that play a crucial role in the absorption of water and nutrients from the soil.

2. **Origin of Root Hairs**:
- These structures originate from cells known as trichoblasts, which are found in the root epidermis.

3. **Structure of Root Hairs**:
- Root hairs are characterized by their hair-like appearance. They are typically thin-walled and unbranched, which facilitates their primary function of absorption.

4. **Cellularity of Root Hairs**:
- The key feature of root hairs is that they are unicellular, meaning each root hair is formed from a single cell. This is important for their function, as it allows for efficient absorption.

5. **Evaluating the Options**:
- Now, let's evaluate the options provided:
- (a) always unicellular - This is correct as root hairs are indeed unicellular.
- (b) sometimes unicellular - This is incorrect.
- (c) sometimes multicellular - This is incorrect.
- (d) always multicellular - This is incorrect.

6. **Conclusion**:
- Based on the information, the correct answer is (a) always unicellular.