Some examples of changes are given below:
a. Sawing of wood b. Breaking down of ozone C. Melting of an ice cream d. Making biogas from cowdung e. Digestion of food f. Baking a clay pot
Classify the above changes into
I. Irreversible physical change II. Chemical change III. Reversible physical change

Options

A. I-a, f, II - b, d, e, III - C
B. I - a, b, e, II - d, f, III - c
C. I-a, II - b, d, e, f, III - c
D. I- f, II -c, e, III - a, b, d

Explanation

To classify the given changes into the categories of irreversible physical change, chemical change, and reversible physical change, we will analyze each example one by one.

### Step-by-Step Solution:

1. **Sawing of wood (a)**:
- This is an irreversible physical change. Once wood is sawed, it cannot be returned to its original form as a whole piece of wood.
- **Classification**: Irreversible Physical Change

2. **Breaking down of ozone (b)**:
- This is a chemical change. The breaking down of ozone involves a change in its chemical structure, resulting in different substances.
- **Classification**: Chemical Change

3. **Melting of an ice cream (c)**:
- This is a reversible physical change. Ice cream can melt and then be refrozen back to its original state.
- **Classification**: Reversible Physical Change

4. **Making biogas from cow dung (d)**:
- This is a chemical change. The process involves the decomposition of organic matter, resulting in new substances (biogas).
- **Classification**: Chemical Change

5. **Digestion of food (e)**:
- This is also a chemical change. During digestion, food is broken down into simpler substances that the body can use, which involves chemical reactions.
- **Classification**: Chemical Change

6. **Baking a clay pot (f)**:
- This is a chemical change. When clay is baked, it undergoes a chemical transformation to become a hard, durable material.
- **Classification**: Chemical Change

### Summary of Classifications:
- **Irreversible Physical Change**: a (Sawing of wood)
- **Chemical Change**: b (Breaking down of ozone), d (Making biogas from cow dung), e (Digestion of food), f (Baking a clay pot)
- **Reversible Physical Change**: c (Melting of an ice cream)

### Final Classification:
- I. Irreversible Physical Change: a
- II. Chemical Change: b, d, e, f
- III. Reversible Physical Change: c