The correct answer is that the shells of clams and other mollusks dissolve when the pH becomes more acidic.
This is because the shells of clams and other mollusks are made of calcium carbonate that is dissolved in acidic conditions. The pH needs to be low to dissolve calcium carbonate into it. It takes few days to dissolve the shell completely.
Answer:
Having bacteria would produce organic molecules and defeat the whole purpose of the experiment which is to make organic molecules from inorganic molecules. The experiment was supposed to demonstrate the formation of the first organic molecules that initiated life on primordial earth. It is believed that lightning powered the formation of the first simple amino acids, like glycine, from the primordial atmosphere which was mainly composed of carbon dioxide and methane.
