Movements caused by internal factors are

Options

A. Paratonic
B. Intrinsic
C. Autonomic
D. Rheotropism.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for movements in plants that are caused by internal factors. We need to analyze the given options to determine which one fits this description.

2. **Analyzing the First Option - Paratonic**:
- Paratonic movements are responses to external stimuli.
- These movements are directional and depend on external factors (like light or gravity).
- Therefore, Paratonic is not caused by internal factors.
- **Conclusion**: This option is incorrect.

3. **Analyzing the Second Option - Intrinsic**:
- Intrinsic movements are related to genetic factors.
- While genetic factors are internal, intrinsic movements do not specifically refer to plant movements but rather to the inherent characteristics of the plant.
- Thus, this option does not directly refer to movements caused by internal factors.
- **Conclusion**: This option is also incorrect.

4. **Analyzing the Third Option - Automatic**:
- Automatic movements are spontaneous and occur without external stimuli.
- These movements are indeed caused by internal factors, such as the protoplast movement in plants.
- Automatic movements are often observed in aquatic plants, where they respond to internal conditions rather than external stimuli.
- **Conclusion**: This option is correct.

5. **Analyzing the Fourth Option - Rheotropism**:
- Rheotropism refers to the growth of plants in response to water currents, which is an external factor.
- Since it is a response to an external stimulus, it does not qualify as a movement caused by internal factors.
- **Conclusion**: This option is incorrect.

6. **Final Answer**: The correct answer to the question "Movements caused by internal factors are" is **Automatic**.

---