Etiolation is characterised by

Options

A. Slender yellowish stems
B. Small yellowish leaves
C. Subterminal hook
D. All the above.

Answer

### Step-by-Step Solution:

1. **Understanding Etiolation**: Etiolation is a physiological response of plants that occurs when they are grown in conditions of low light or complete darkness. This process is particularly common in flowering plants.

2. **Characteristics of Etiolated Plants**:
- **Slender Yellowish Stems**: In the absence of sufficient light, plants tend to grow taller and thinner as they stretch towards any available light source. This results in stems that are elongated and have a yellowish hue.

- **Small Yellowish Leaves**: The leaves of etiolated plants are often smaller and yellowish. This yellowing, known as chlorosis, occurs because the plants are not producing enough chlorophyll due to the lack of light.

- **Sub-terminal Hook**: Etiolated plants may also exhibit a sub-terminal hook, which is a bending of the stem that helps the plant to navigate towards light.

3. **Conclusion**: Given the characteristics mentioned, etiolation is characterized by slender yellowish stems, small yellowish leaves, and a sub-terminal hook. Therefore, the correct answer is "all the above."

### Final Answer:
Etiolation is characterized by slender yellowish stems, small yellowish leaves, and a sub-terminal hook, which means the answer is "all the above."

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