Maurice put some dirt and water into a jar. After shaking the jar, the contents turned brown. He set the jar on the table and checked it every five minutes for twenty minutes. The diagram below shows what he saw. Which of the following did Maurice make with the dirt and water?

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.