NEED HELP with this science

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

If t=tall and t=short what will be the physical appearance of the offspring the cross below? a.some will be tall and some will be short b.they will all be tall c.they will all be short d.they will be medium height

The graph shows the area of forest cover in various regions of the world through a forest station forest habitats have been established in areas that previously didn't have forest and with geographic region has this approach been most successful