(A) : Alanine is one of the basic units of protein.
(R ) : All kinds of amino acids are considered basic units of protein.

Options

A. Both (A) and (R ) are true and (R ) is the correct explanation of (A)
B. Both (A) and (R ) are true and (R ) is not the correct explanation of (A)
C. (A) is true but (R ) is false
D. (A) is false but (R ) is true

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion (A)**: The assertion states that "Alanine is one of the basic units of protein." To evaluate this, we need to recognize that proteins are made up of amino acids, which are the building blocks of proteins. Alanine is indeed an amino acid.

2. **Identifying Alanine**: Alanine is classified as an alpha-amino acid. It has the general structure of amino acids, which includes an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (in the case of alanine, this side chain is a methyl group, -CH3).

3. **Understanding the Reason (R)**: The reason states that "All kinds of amino acids are considered basic units of protein." To evaluate this, we need to clarify what is meant by "all kinds of amino acids." While it is true that amino acids are the building blocks of proteins, not all amino acids are incorporated into proteins. Only specific amino acids, particularly the alpha-amino acids, are used in protein synthesis.

4. **Evaluating the Truth of the Statements**:
- The assertion (A) is true because alanine is indeed one of the basic units of protein.
- The reason (R) is false because it incorrectly states that all kinds of amino acids are considered basic units of protein. In reality, only L-type alpha-amino acids are used in protein synthesis.

5. **Conclusion**: Based on the evaluation, we conclude that the assertion is true, but the reason is false. Therefore, the correct answer is that A is true, but R is false.

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