Breathing is a chemical process. When air is breathed in, it reacts chemically; when a person breathes out, they release more carbon dioxide than they breathed in, and less oxygen.
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Jyotsna Singh answered this
Breathing is a chemical change, Fireworks going off is an Chemical change Boiling water added to instant coffee is a physical change because the chemical makeup is not changing. A plant making food by photosynthesis is a Chemical change.
The key point about physical and chemical changes is.
A Chemical change is one that is near impossible to change back. It only occurs when a new substance is produced or the original substance disappears.
