3. Which statement correctly defines digestion? Digestion is a reversible process due to mechanical digestion.
Digestion is the process of breaking down food into smaller molecules.
Digestion is mixing food with saliva, which is when mechanical digestion starts.
Digestion is the process of chewing food, which is referred to as chemical digestion.

What is the significance of the protein-lined pits? a. protein attracts other proteins needed for atp synthesis within the cell. b. protein-lined pits are able to transport one molecule at a time down the concentration gradient within the cell. c. the polarity of proteins allows other polar molecules to attach and be transported in the cell by transport channels. d. receptors within the pits allow ligands to fuse and be transported into the cell by endocytosis.