Assertion: All amino acids exists as Zwitter ions.
Reason: Amino acids have both `- NH_(2)` and `-COOH` group

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the corret explanation of the assertion.
C. If assertion is true but reason is false.
D. If the assertion and the reason both are false.

Explanation

To solve the question regarding the assertion and reason about amino acids and zwitterions, we can break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "All amino acids exist as zwitter ions." A zwitterion is a molecule that has both positive and negative charges but is overall neutral.

2. **Understanding the Reason**:
- The reason provided is that "Amino acids have both -NH2 (amino) and -COOH (carboxyl) groups." This is crucial because the presence of these two functional groups is what allows amino acids to exist as zwitterions.

3. **Analyzing the Structure of Amino Acids**:
- Amino acids consist of a central carbon atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group).
- The carboxyl group can donate a proton (H+) and become negatively charged (-COO⁻), while the amino group can accept a proton and become positively charged (-NH3⁺).

4. **Formation of Zwitterions**:
- In a solution, the carboxyl group loses a hydrogen ion (H+) and becomes negatively charged, while the amino group gains a hydrogen ion and becomes positively charged.
- This results in the zwitterionic form of the amino acid, where the molecule has both a positive and a negative charge but is overall neutral.

5. **Conclusion**:
- Since all amino acids contain both -NH2 and -COOH groups, they can all exist as zwitterions. Therefore, the assertion is true.
- The reason correctly explains why the assertion is true, as the presence of both functional groups is necessary for zwitterion formation.

### Final Answer:
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.