Name the three main groups of food with two examples each?

Q. Name the six main nutrients present in food, with one example of its source.

Q. Food is classified into three groups on the basis of the function they perform in our body. Name the three groups, and briefly give their functions. Also, give their two sources for each.

Q. Name the three major constituents of balanced diet with two examples for each.
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Q. Name the two groups into which phenomenon of catalysis can be divided. Given an example of each group with the chemical equation involved.