As the 20^th Century Approched and During Its Early Decades

As the 20^th century approched and during its early decades major discoveries began to show how life sustaining activities were regulated and

A) Claude Bernard discovered hormones
B) Walter H. Gaskill concluded that the involuntary system had antagonistic components
C) Walter Cannon named the autonomic nervous system
D) Ivan Pavlov proposed the milieu interiur to explain his finding tha dogs could salivate to the sound of a bell