What was first responsible for changing the formerly poisonous atmosphere to an oxygen-rich atmosphere ss we have today

Identify the image that doesn’t depict a reproductive strategy. 1st image: a bird feeding their young residing in a nest. 2nd image: a lioness nestled with her young. 3rd image: leaves of a tree during the day time. 4th image: a fish gazing up at what appears to be bubbles or mosquito eggs.

Compare the composition of the moon's surface with the composition of the earth's surface.

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?