Which of the following is true for diffusion?
I. It is a slow process,
II. It does not depend on a living system
III. It is very important to plants since it is the only means for gaseous movement within the plant body.
IV. Diffusion is very obvious in gases and liquids, but diffusion in solid rather than of solid is more likely

Options

A. All are correct
B. Only Il is correct
C. Only I and II are correct
D. None

Answer

To determine which statements about diffusion are true, we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Evaluate Statement I: "It is a slow process."**
- Diffusion is indeed a slow process because it does not require energy (ATP) to occur. It relies on the random movement of particles, which takes time. Therefore, this statement is **true**.

2. **Evaluate Statement II: "It does not depend on a living system."**
- Simple diffusion occurs without the need for a living system or cellular energy. It can happen in any medium (gas, liquid, or solid) regardless of whether the system is alive. Thus, this statement is also **true**.

3. **Evaluate Statement III: "It is very important to plants since it is the only means for gaseous movement within the plant body."**
- In plants, diffusion is indeed the primary method for gas exchange (such as oxygen and carbon dioxide) because they lack a circulatory system. Hence, this statement is **true**.

4. **Evaluate Statement IV: "Diffusion is very obvious in gases and liquids, but diffusion in solid rather than of solid is more likely."**
- This statement is correct because diffusion occurs more readily in gases and liquids due to the greater distance between particles. In solids, diffusion is much slower due to closely packed particles. The phrase "diffusion in solid rather than of solid" is somewhat confusing but can be interpreted to mean that diffusion can occur within solids, albeit at a much slower rate. Therefore, this statement is **true**.

### Conclusion:
All four statements about diffusion are true.

### Final Answer:
All statements (I, II, III, and IV) are true regarding diffusion.

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