​Loewi Demonstrated That Synapses Operate by the Release of Chemicals

Multiple Choice

​Loewi demonstrated that synapses operate by the release of chemicals by ____.

A) applying adrenaline directly to the heart muscle
B) ​collecting fluid from a stimulated frog's heart, transferring it to another frog's heart, and measuring that heart rate
C) ​measuring the speed of a dog's reflexes while the dog was under the influence of various drugs
D) applying an extract of marijuana in eye drops and discovering that it dilated the pupils