Question

the earth formed approximately billion years ago. the early earth had a environment. volcanic activity spewed toxic gases such as and hydrogen sulfide. temperatures were high as meteorites and asteroids bombarded the surface with numerous which lessened about billion years ago. many scientists believe that once collisions were reduced, then life forms may have originated around billion years ago. this evidence was oxygen methane oceans hostile photosynthetic 3.5 cyanobacteria stromatolites 3.8 explosions 4.6 crust

Explanation:

The Earth formed about 4.6 billion years ago. The early - Earth environment was hostile with volcanic activity releasing toxic gases like methane. Meteorite and asteroid impacts caused numerous explosions which lessened around 3.8 billion years ago. Life is thought to have originated around 3.5 billion years ago.

Answer:

4.6, hostile, methane, explosions, 3.8, 3.5