Im doing social studies and i need help ;-;

What impact did improvements in farming technology near the end of the nineteenth century have on the american economy? a. more energy was needed to power equipment, creating the renewable energy industry. b. less labor was necessary on farms, leading workers to pursue other jobs. c. less money was invested in farming as many locally owned farms went bankrupt. d. more demand for agricultural products reduced the price of food and animal products.

Aresearcher conducts a focus group to learn about attitudes towards hygiene and disease prevention. two weeks after the focus group, the researcher learns one of the subjects had a heart attack at home and was hospitalized, but made a full recovery. based on dhs regulations, the researcher report this event to the irb? no, this does not need to be reported since the subject had the heart attack when they were home, not at the focus group.no, this does not need to be reported since it is unrelated to participation in the study.no, this does not need to be reported because two weeks have passed.no, this does not need to be reported since the subject recovered.

What greek scientist created a screw to move water for irrigation?