The directions are above the table so can u answer it in table form

Could someone me with number one you

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

Genetic orders can result when sister chromatids fail to separate properly during which phase is this problem most likely to occur