In 1939, the use of ddt (a powerful synthetic chemical) as an insecticide was discovered. the united states adopted its widespread use, producing up to 100 million kilograms per year (200 million pounds per year). twenty years later, severe side effects started to be reported as a result of ddt use. which was an advantage of using ddt?
insect and pest populations decreased
birth defect rates increased
cancer rates increased
fertility rates decreased