To order the events in Earth's history from earliest to most recent, we need to consider the geological and biological developments.
- Photosynthesizing bacteria release oxygen into the sea. (This marks the beginning of oxygen production).
- Oxygen concentrations in the sea increase due to photosynthesizing bacteria. (This follows the release of oxygen by bacteria).
- Oxygen concentrations in the atmosphere increase. (Once enough oxygen has built up in the seas, it eventually starts to accumulate in the atmosphere).
- Single-celled organisms increase atmospheric methane. (This can happen after oxygen levels have risen, which can be associated with other biological changes).
- New animal species evolve on land. (The increase in oxygen allows for more complex life forms, eventually leading to the evolution of land animals).
The correct order would be:
- Photosynthesizing bacteria release oxygen into the sea.
- Oxygen concentrations in the sea increase due to photosynthesizing bacteria.
- Oxygen concentrations in the atmosphere increase.
- Single-celled organisms increase atmospheric methane.
- Many new land animals evolve.
Thus, the correct response is:
Photosynthesizing bacteria release oxygen into the sea. Oxygen concentrations increase in the atmosphere. Single-celled organisms increase the amount of atmospheric methane. Many new land animals evolve.