Which of the following is an example of chemical reaction

A chemical reaction happens when one or more chemicals are changed into one or more other chemicals. Examples: iron and oxygen combining to make rust. vinegar and baking soda combining to make sodium acetate, carbon dioxide and water.

Explanation:

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answer: the answer is b

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.