Explain the significance of what Loewi observed in his experiment with the two frog hearts.

A. It showed that neurons communicate with muscle by electrical signals.
B. It suggests that a chemical substance released from the first heart, when added to the second heart, reproduced the effects of electrical stimulation.
C. It suggests that all vertebrate hearts receive both inhibitory and excitatory signals from different nerves.
D. It showed that nerves have a direct electrical effect on heart muscle.



B. It suggests that a chemical substance released from the first heart, when added to the second heart, reproduced the effects of electrical stimulation.

Biology & Microbiology

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