The plants growing in dark ,show yellowing of leaves and elongated internodes, this condition is called as
(a) Etiolation
(b) Chlorosis
(c) Dechlorosis
(d) Dark effect

Options

A. Etiolation
B. Chlorosis
C. Dechlorosis
D. Dark effect

Answer

To solve the question, "The plants growing in dark show yellowing of leaves and elongated internodes, this condition is called as," we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Condition**: The question describes a condition where plants are growing in the dark, leading to yellowing of leaves and elongated internodes. This is a specific physiological response of plants to low light conditions.

2. **Analyzing Option (a) Etiolation**:
- Etiolation is a phenomenon observed in plants that grow in the absence of light.
- In this condition, plants exhibit rapid stem elongation (elongated internodes) and a pale yellow color due to insufficient chlorophyll production.
- This matches the description given in the question.

3. **Analyzing Option (b) Chlorosis**:
- Chlorosis refers to the yellowing of plant leaves due to a lack of chlorophyll.
- This can occur due to various factors, including nutrient deficiencies (like iron) or inadequate light.
- While chlorosis involves yellowing of leaves, it does not specifically refer to the elongation of internodes.

4. **Analyzing Option (c) Dechlorosis**:
- Dechlorosis is not a commonly recognized term in plant physiology. It seems to imply a reversal of chlorosis, which is not relevant to the condition described.

5. **Analyzing Option (d) Dark effect**:
- "Dark effect" is not a standard term used in plant biology to describe the condition of plants growing in darkness.

6. **Conclusion**:
- Based on the analysis, the most appropriate answer that encompasses both the yellowing of leaves and the elongation of internodes due to growth in the dark is **(a) Etiolation**. While (b) Chlorosis describes part of the condition, it does not account for the elongation of internodes.

### Final Answer:
The correct answer is (a) Etiolation.