Place the following events in the order in which they occurred on the vertical timeline. The first event and the last event have already been entered on the timeline.

1.Oceans contain organic molecules
2.
3.
4.
5.
6.
7.
8.Eukaryotes develop

Choices:
Organisms use photosynthesis
Ozone layer develops
Complex organic molecules form
Organisms use chemosynthesis
Protocells develop
Prokaryotes appear

1) Oceans contain simple organic molecules

2) Complex organic molecules form

3) Protocells develop

4) Prokaryotes develop

5) Organisms use chemosynthesis

6) Organisms use photosynthesis

7) Ozone layer develops

8) Eukaryotes develop

Explanation:

The early conditions of the Earth were not favorable for the support of life on it. Gradually, the Earth cooled down and inorganic gases and organic molecules started constituting the Earth.The organic molecules such as complex lipids gave rise to the protocell. The evolution of the protocells gave rise to the prokaryotes. Scientific hypothesis have claimed that the first type of metabolism that took place on the Earth was in the form of chemosynthesis.The processes of cellular respiration as well as photosynthesis evolved after chemosynthesis.The development of metabolic processes caused more gases to be formed and the ozone layer to be built.The building of the ozone layer provided stable conditions for the Eukaryotes to develop and survive on the Earth.