Diffusion is important for plants as it is the only means for movement of .............. within the plant body.

Options

A. Gases
B. Organic Nutrients
C. Minerals
D. Water

Answer

**Step-by-Step Solution:**

1. **Understanding Diffusion**: Diffusion is a process where molecules move from an area of higher concentration to an area of lower concentration. This movement occurs along a concentration gradient and does not require energy (ATP), making it a passive transport mechanism.

2. **Identifying the Context**: The question asks about the movement of substances within the plant body that occurs solely through diffusion.

3. **Evaluating the Options**:
- **Gases**: Gases, such as oxygen and carbon dioxide, move through diffusion. In plants, gases are exchanged during processes like photosynthesis and respiration.
- **Organic Nutrients**: These typically require active or facilitated transport mechanisms for movement, as they cannot solely rely on diffusion.
- **Minerals**: Similar to organic nutrients, minerals often require active transport to move across plant membranes.
- **Water**: While water can move through osmosis (a type of diffusion), it is not the only means of transport; it can also be moved actively.

4. **Conclusion**: Since gases are the only substances that are transported solely by diffusion within the plant body, the correct answer to fill in the blank is "gases".

**Final Answer**: Gases

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