Which event in Earth’s history most directly allowed life to exist on land? Earth’s temperatures increased, causing widespread evaporation. Earth collided with a large object, forming the moon. Single-celled organisms released oxygen into the air when they photosynthesized. Single-celled organisms absorbed harmful gases from the air when they first formed.

The image shows the evolution of a species of fish. a few fish from a population developed different social behaviors and evolved into different species. two fish according to the image, the fish underwent . the new species of fish had mating seasons that were different from that of the original fish. because of the differences in mating seasons, the fish underwent reproductive isolation. this mode of isolation would be .