試題詳解

26. The secretion of hormone A causes an increase in activity X in an organism. If this mechanism works by positive feedback, which of the following statements represents that fact ?
(A) An increase in X produces an increase in A.
(B) An increase in A produces an increase in X.
(C) An increase in X produces a decrease in A.
(D) A decrease in A produces an increase in X.
(E) Both A and B are correct.