This section contains Assertion and Reason type questions .Each question has 4 choices (1)(2)(3) and (4) out of which only one is correct
Assertion(A): cheese gives foul smell when left open in summer
Reason:The reaction which occur by absorption of heat is known as hypothermic reaction.

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that cheese gives a foul smell when left open in summer. This is true because cheese, being a dairy product, can spoil due to microbial activity and oxidation when exposed to air, especially in warm temperatures.

**Hint:** Consider the conditions that affect food spoilage, especially temperature and exposure to air.

2. **Understanding the Reason:**
- The reason provided states that the reaction which occurs by absorption of heat is known as an endothermic reaction. This definition is correct, but it does not directly relate to the spoilage of cheese.

**Hint:** Reflect on the definitions of endothermic and exothermic reactions and how they relate to food spoilage.

3. **Analyzing the Relationship:**
- While both the assertion and the reason are true statements, the reason does not explain why cheese gives a foul smell. The foul smell is due to rancidity caused by oxidation, not specifically because of an endothermic reaction.

**Hint:** Think about how the processes of rancidity and spoilage occur and whether they involve heat absorption.

4. **Conclusion:**
- Since the assertion is true and the reason is also true but does not support the assertion, the correct choice is that both statements are true, but the reason does not support the assertion.

**Final Answer:** The correct option is (2) - both A and R are true, but R is not the correct explanation of A.