Pritoplasmic streaming is

Options

A. Thigmonastic movements
B. Photonasty
C. Movement of locomotion
D. Movement of curvature

Answer

### Step-by-Step Text Solution

1. **Understanding the Term**: The term "protoplasmic streaming" refers to the movement of cytoplasm within a cell. This is a vital process that facilitates the distribution of nutrients, organelles, and other substances throughout the cell.

2. **Nature of the Movement**: Protoplasmic streaming is characterized as a rapid and autonomous movement. This means that it occurs naturally and does not require external stimuli to initiate.

3. **Function of Protoplasmic Streaming**: This movement is crucial for cellular functions, as it helps in the transportation of materials within the cell, thereby supporting various metabolic processes.

4. **Comparison with Other Movements**:
- **Thigmonastic Movement**: This is a response to tactile stimuli, such as touch, and is not related to protoplasmic streaming.
- **Photonasty**: This refers to movements in plants in response to light, such as the opening and closing of flowers, which is also different from protoplasmic streaming.
- **Movement of Curvature**: This involves the bending of plant organs in response to stimuli, which is again distinct from the concept of protoplasmic streaming.

5. **Conclusion**: Based on the definitions and comparisons, protoplasmic streaming can be defined as the rapid movement of cytoplasm within the cell, primarily serving the function of locomotion and distribution of materials.