Spoilage of food or milk in summers is an example of ______ changes.

Options

A. Fast, reversible, chemical
B. Slow, reversible, desirable
C. Slow, irreversible, undesirable
D. Slow, irreversible, physical

Explanation

To determine the type of change represented by the spoilage of food or milk in summers, we can analyze the characteristics of this process step by step.

### Step-by-Step Solution:

1. **Identify the Nature of the Change**:
- The spoilage of food or milk occurs over time, rather than instantaneously. This indicates that it is a slow change.

**Hint**: Think about how long it takes for food to spoil. Is it immediate or gradual?

2. **Determine Reversibility**:
- Once food or milk has spoiled, it cannot be restored to its original state. This means that the change is irreversible.

**Hint**: Consider if you can make spoiled milk fresh again. What happens to it?

3. **Assess Desirability**:
- Spoilage is generally not desired by anyone. People do not want their food or milk to spoil, making this change undesirable.

**Hint**: Ask yourself if anyone would want their food to spoil. Is it a good thing or a bad thing?

4. **Combine the Characteristics**:
- Based on the analysis:
- It is a **slow** change.
- It is **irreversible**.
- It is **undesirable**.

5. **Select the Correct Option**:
- Given the characteristics identified, the correct answer is:
- **C. Slow, irreversible and undesirable**.

### Final Answer:
The spoilage of food or milk in summers is an example of **C. Slow, irreversible and undesirable changes**.