Which of the following is not a mineral ion?

Options

A. `NO_3^(-)`
B. `Mg^(2+)`
C. `CO_2`
D. `Al^(3+)`

Answer

To determine which of the following options is not a mineral ion, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Mineral Ions**:
- Mineral ions are inorganic ions that are essential for plant growth and development. They are typically derived from the soil and are absorbed by plants through their roots.

2. **Identify the Options**:
- The question provides several options, one of which is CO2 (carbon dioxide).

3. **Analyze CO2**:
- Carbon dioxide is a gas that is present in the atmosphere. It is not an ion; rather, it is a molecular compound made up of carbon and oxygen atoms.

4. **Determine the Nature of Other Options**:
- The other options (not provided in the question) would typically include various mineral ions such as potassium (K+), calcium (Ca2+), magnesium (Mg2+), etc. These are all charged particles (ions) that plants utilize.

5. **Conclude**:
- Since CO2 is a gas and not an ion, it is the correct answer to the question of which option is not a mineral ion.

### Final Answer:
- The correct answer is CO2 (carbon dioxide), as it is not a mineral ion.

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