Answer:
1. giant impact forms moon
2. end of heavy bombardment
3. early life (based on fossil evidence))
4. oxygen buildup in atmosphere
5. earliest mammals
6. dinosaurs go extinct
7. earliest humans
Explanation:
The Earth has a very interesting past, with lot of changes and turnarounds in it. If we sum it up quickly, we can say that soon after the Earth formed and collided with another large space object, part of the Earth was torn away, which eventually formed the moon. The Earth was constantly bombarded by meteorites and asteroids, but that came to an end as the atmosphere was becoming denser and denser. The first life started to develop in the oceans in the form of cyanobacteria, which used photosynthesis, and were constantly releasing oxygen, building it up int he atmosphere. The oxygen changed the living conditions, enabling the life to thrive and diversify. The dinosaurs and mammals eventually came on the scene, with the dinosaurs coming first by around 20 million years, giving them the edge to become the dominant life form. The mammals lived in the shadows until the dinosaurs existed, but their reign ended with a large meteorite collision. This prompted the quick evolution and diversification of the mammals, quickly becoming the dominant life form, and just few million years ago they gave rise to the earliest human ancestors, the hominids.
