Question

what is not a function of a protein? cell transport cell - to - cell communication main energy source catalyze chemical reactions

Explanation:

Proteins can facilitate cell - transport (e.g., carrier proteins), cell - to - cell communication (e.g., receptor proteins), and catalyze chemical reactions (enzymes are proteins). However, the main energy source for cells is carbohydrates, not proteins.

Answer:

C. Main energy source