__are constructed from amino acids, and some of these are only available to our bodies if they are ingested

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fats proteins carbohydrates

water air food

the answers is proteins and food

Proteins are constructed from amino acids, and some of these are only available to our bodies if they are ingested as food.

Option D

Explanation:

The proteins are heteropolymers made up of many monomers that are the amino acids, there are 2 types of amino acids they are the essential and the non-essential amino acids, the non-essential amino acids are present within the body whereas the essential amino acids need to be supplemented through food. The combination of both amino acids are required for stable formation of proteins.

friedrich meischer discovered it in white blood cell