What is true about assertion a and reason r?
Assertion a. The 'biological species' concept helps us to ask how species are formed.
Reason r. The concept of biological species focusses our attention on the question of how reproductive isolation comes about
(a) Both a and r are correct but r does not explain a
(b) Both a and r are correct and r is true explanation of a
(c) both a and r are not true
(d) Only a is true, r is not correct

Options

A. Both a and r are correct but r does not explain a.
B. Both a and r are correct and r is true explanation of a
C. both a and r are not true
D. Only a is true, r is not correct

Answer

To determine the truth of the assertion (A) and reason (R), we need to analyze both statements carefully.

### Step 1: Analyze the Assertion (A)
The assertion states: "The biological species concept helps us to ask how species are formed."

- The biological species concept defines a species based on the ability of individuals to interbreed and produce fertile offspring. It focuses on reproductive isolation and the potential for gene flow between populations.
- However, the assertion implies that the concept directly addresses how species are formed, which is not entirely accurate. The biological species concept does not explain the mechanisms of speciation; it merely categorizes species based on reproductive capabilities.

**Conclusion for A**: The assertion is **incorrect**.

### Step 2: Analyze the Reason (R)
The reason states: "The concept of biological species focuses our attention on the question of how reproductive isolation comes about."

- Reproductive isolation is indeed a key factor in the biological species concept, as it prevents different species from interbreeding. However, the reason suggests that the biological species concept itself is focused on how reproductive isolation occurs.
- While reproductive isolation is an important aspect of the biological species concept, the concept does not primarily focus on explaining the mechanisms of reproductive isolation. Instead, it categorizes species based on existing reproductive barriers.

**Conclusion for R**: The reason is also **incorrect**.

### Step 3: Determine the Correct Option
Since both the assertion (A) and the reason (R) are incorrect, the correct option is:

(c) both A and R are not true.

### Final Answer
The correct answer is (c) both A and R are not true.

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