試題詳解

11. Otto Loewi performed an experiment in which he electrically stimulated the vagus nerve connected to one frog heart. Loewi also let the fluid bathing this first heart pass to a second chamber containing a second frog heart not connected to a nerve. What did Loewi observe?
(A) There was no effect on the beating of either heart.
(B) The first heart showed a decrease in beat rate and so did the second heart.
(C) The first heart showed an increase in beat rate and so did the second heart.
(D) The first heart showed a decrease in beat rate, but there was no change in the second heart.
(E) The first heart showed an increase in beat rate, but there was no change in the second heart.