Which of the following statements about positive feedback mechanisms is not true? a. Positive feedback mechanisms can result from human activity. b. Positive feedback mechanisms can occur naturally. c. Positive feedback mechanisms lead to increased change. d. Positive feedback mechanisms reduce change in a system. Please select the best answer from the choices provided A B C D

Cancer cells spread to other parts of the body by entering the bloodstream. which of the following organs could prevent a cancer cell in the bloodstream from spreading, and why? a. the spleen, because it releases lymphocytes into the blood b. the peyer's patches, because they release lymphocytes into the blood c. the lymph nodes, because they release lymph into the blood d. the thymus, because it releases lymph into the blood