Different combinations of amino acids give different properties to proteins. Therefore, the main feature that should be used in distinguishing proteins from each other is the amino acid sequence of proteins. However, proteins can be distinguished by their size and the biochemical properties as well.
Answer:
Sandstone does not react with Hydrochloric acid. The acid soaks into the rock because the rock is porous, filled with tiny holes. It is made up of tiny grains of sand cemented together by intense pressure.