I’ll mark brainliest

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

Select the correct answer. what is the observable characteristic of a person called? o a. genotypephenotypeoc. alleleo d. gene

Achange in which factor will affect the rate of reaction only when gases are involved? temperature pressure surface area concentration