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

Mars and earth have quite a few things in common. both are  terrestrial planets, both are located within the sun’s  habitable zone, both have  polar ice caps, similarly  tilted axes, and similar  variations in temperature. and according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that mars once had a  dense atmosphere  and was covered with  warm, flowing water.