Some bacteria live in the human digestive tract. Here bacteria finds a good environment to obtain nutrients. Humans improve the health of their digestive tract due to the presence of this bacteria
A. predation
B. commensalism
C. parasitism
D. mutualism

5. what might happen if you were to remove all light from the setup after the discs have all become buoyant? describe what you would see. explain why this would occur with relation to cellular processes like respiration. [referring to an ap biology lab in which spinach discs are placed in a sodium bicarbonate solution and exposed to light.]