Graph showing birth rate in the U. S. from 1945-1990.
Primary source or secondary?

1. what was william harvey's discovery about the human body? @ two types of blood flowed through the veins and arteries. b four fluids existed in the body: blood, yellow bile, black bile, and phlegm. © the same blood flowed through the veins and arteries. d ancient ideas of human anatomy and bodily functions were wrong. done