I think the answer is c) the preservatives slow the growth og mold and bacteria
Answer:
Active transport: movement against a gradient To move substances against a concentration or electrochemical gradient, a cell must use energy. Active transport mechanisms do just this, expending energy (often in the form of ATP) to maintain the proper concentrations of ions and molecules in living cells.
No they cant be mechanical because then something would have to generate their rays through the inventing of a machine.
