Tropic movements occur as a result of

Options

A. Unidirectional effect of environmental factors on plant organs
B. Bidirectional effect of environmental factors on plant organs
C. Multidirectional effect of environmental factors on plant organs
D. No effect of environmental factors on plant organs/

Answer

**Step-by-Step Solution:**

1. **Understanding Tropic Movements**:
- Tropic movements are directional growth movements that occur in response to environmental stimuli. They are classified based on the direction of the stimulus.

2. **Identifying the Nature of Stimuli**:
- The stimuli that cause tropic movements are typically unidirectional, meaning they come from one specific direction (e.g., light, gravity, water).

3. **Evaluating the Options**:
- **Option 1**: Unidirectional effect of environmental factors on plant organs.
- This option aligns with the definition of tropic movements since they respond to stimuli from a single direction.
- **Option 2**: Bidirectional effect of environmental factors on plant organs.
- This is incorrect because tropic movements do not respond to stimuli coming from two directions.
- **Option 3**: Multidirectional effects of environmental factors on plant organs.
- This is also incorrect as tropic movements are not influenced by multiple directions simultaneously.
- **Option 4**: No effect of environmental factors on plant organs.
- This is incorrect because environmental factors are crucial for the occurrence of tropic movements.

4. **Conclusion**:
- Based on the evaluation of the options, the correct answer is **Option 1**: Unidirectional effect of environmental factors on plant organs.

---