In which among the following changes, does the molecular composition remain the same? Justify.
(a) Photosynthesis (b) Digestion of food
(c ) Formation of clouds (d) Moulding of glass
(e) Melting of butter (f) Perspiration

Explanation

To determine which among the given changes has the same molecular composition, we need to analyze each option based on whether it represents a physical change or a chemical change.

1. **Photosynthesis (a)**: This is a chemical change. During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen, changing the molecular composition.

2. **Digestion of food (b)**: This is also a chemical change. The food is broken down into simpler substances, altering its molecular composition.

3. **Formation of clouds (c)**: This is a physical change. Water vapor condenses into tiny droplets to form clouds, but the molecular composition of water (H₂O) remains unchanged.

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