Which of these best demonstrates mutualism between certain types of bacteria and humans? A. Invasive bacteria, located at an area of injury produce toxin that damage healthy tissue of the human body.
B. Bacteria in improperly prepared food is consumed by humans, causing food poisoning.
C. Bacteria become resistant to antibacterial medication that humans use for treatment.
D. Intestinal bacteria obtain nutrients from the gut and produce vitamin K used by humans.