The concept that life was organized into a fixed hierarchy from simple to complex was prevalent well into the 19th century in europe and the united states. this is referred to as

a. poison gas was sprayed over battlefields by airplanes to weaken enemy positions before major attacks.

the two atomic bombs dropped on japan in 1945 killed and maimed hundreds of thousands of people, and their effects are still being felt today. the uranium bomb detonated over hiroshima on 6 august 1945 had an explosive yield equal to 15,000 tonnes of tnt.