All are correct about micronutrients except.

Options

A. Role in enzyme activation is secondary
B. Little role in protoplasmic structure
C. Do not cause osmotic potential
D. Become toxic in excess

Answer

To solve the question "All are correct about micronutrients except," we need to analyze the provided statements regarding micronutrients and identify the incorrect one. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Role of Micronutrients
Micronutrients are essential elements required by plants in small quantities. They play crucial roles in various physiological processes, including enzyme activation, photosynthesis, and nitrogen metabolism.

**Hint:** Micronutrients are vital for plant health, but they are needed in much smaller amounts compared to macronutrients.

### Step 2: Evaluate Each Statement
1. **Statement 1:** "Role in enzyme activation is secondary."
- This statement is incorrect. Micronutrients like manganese and zinc are critical for activating many enzymes involved in essential processes such as photosynthesis and respiration. Their role in enzyme activation is primary, not secondary.

**Hint:** Consider the importance of micronutrients in enzyme functions.

2. **Statement 2:** "Literal role in protoplasmic structure."
- This statement is correct. While macronutrients (like carbon, hydrogen, and oxygen) are primarily responsible for forming the protoplasmic structure, micronutrients also play a role but are not the main contributors.

**Hint:** Differentiate between the roles of macronutrients and micronutrients in plant structure.

3. **Statement 3:** "Do not cause osmotic potential."
- This statement is correct. Micronutrients are present in very low concentrations and do not significantly influence osmotic potential in plants.

**Hint:** Think about how the concentration of nutrients affects osmotic pressure.

4. **Statement 4:** "Become toxic in excess."
- This statement is correct. Micronutrients can indeed become toxic if present in excessive amounts, as seen with manganese toxicity.

**Hint:** Consider the balance required in nutrient levels for plant health.

### Step 3: Identify the Incorrect Statement
After evaluating all the statements, we find that the first statement is the only incorrect one. Therefore, the answer to the question is:

**Answer:** Option 1 is the incorrect statement about micronutrients.

### Summary
In summary, the incorrect statement about micronutrients is that their role in enzyme activation is secondary. In reality, their role is primary and essential for various metabolic processes in plants.

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