What are the participants in an experiment who are not given the treatment called?

Choose one of these concerns and write a short paragraph about its impact on africa. what has caused this problem to occur, and how has it impacted people who live there?

In 1914, alabama produced 1.7 million bales of cotton, but three years later produced only 515,000, bales. meanwhile, in georgia, 5.2 million acres of land was dedicated for cotton production in 1914, but by 1923 there were just 2.6 million acres used for growing cotton. all of this was the result of the work of a tiny insect: the boll weevil. alabama and georgia first felt the effects of the boll weevil at different times. what would account for this difference in timing?

From where do ocean waves obtain their energy