Assertion: Transgenic mice are being used to test the safety of the polio vaccine
Reason :They could not replace the use of monkeys to test the safety of batches of the vaccine

Options

A. cow
B. mice
C. sheep
D. goat

Answer

To analyze the assertion and reason given in the question, we can break it down into clear steps:

### Step 1: Understand the Assertion
The assertion states that "Transgenic mice are being used to test the safety of the polio vaccine."
- Transgenic mice are genetically modified mice that carry genes from other species. They are often used in biomedical research due to their ability to mimic human disease and response to treatments.

### Step 2: Evaluate the Reason
The reason states that "They could not replace the use of monkeys to test the safety of batches of the vaccine."
- Traditionally, monkeys have been used in vaccine testing because of their physiological similarities to humans. However, the statement implies that transgenic mice cannot serve as substitutes for monkeys in this context.

### Step 3: Analyze the Relationship Between Assertion and Reason
- The assertion is correct because transgenic mice are indeed used in vaccine safety testing.
- The reason is incorrect because transgenic mice can replace monkeys in many testing scenarios, including vaccine safety testing. Other animals, such as guinea pigs, are also used.

### Step 4: Conclusion
Based on the analysis:
- The assertion is true.
- The reason is false.
- Therefore, the correct answer is that the assertion is correct, but the reason is incorrect.

### Final Answer
The correct answer is option D: Assertion is correct, and Reason is incorrect.

---