Which of the following is most likely responsible for the fact that organic molecules no longer formed spontaneously on Earth? A. The amount of UV radiation increased
B. The amount of oxygen in the atmosphere increased
C. Water accumulated in the oceans
D. Earth's surface temperature warmed

Secondary pollutants are more harmful than primary pollutants. select the best answer from the choices provided ot of

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte