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

transformative rocks are the stones that emerge from the transformation of existing rock composes in a procedure called changeability, implies changing of structures. transformative rocks are shaped from alternate shakes that are changing a result of warmth or weight connected. one of this model is the earth developments that making rocks profoundly cover or crushed which will make the stones warmed and put under awesome weight. they are not softening but rather the minerals they are containing are changed synthetically that will shape transformative rocks. now and again different rocks are shaped when the others are near some liquid magma and getting warmed.