What discovery by william harvey greatly advanced the study of physiology?
a. he explained how the nervous system works.
b. he explained how muscles work.
c. he explained the circulation of blood.
d. he explained how the brain works.
i think its c i'm not sure.

the labor movement in the united states grew out of the need to protect the common interest of workers

for those in the industrial sector organized labor unions fought for better wages reasonable hours and safer working conditions

  in the 19th century trade unionism was mainly a movement of skilled workers.

hope this

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explanation: