Which productive resource is defined as tools, machines, and structures used over and over again in the production of goods and services?
O A human resources
OB physical capital
OC human capital
D. natural resources

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