What term is used to describe a species whose population is rapidly decreasing and may disappear completely?

Which entry is in the wrong position in the table?

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

Sequence how oxygen accumulated in the atmosphere and the effect it had on life by completing the flowchart