What is the importance of the endosymbiotic theory?

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

Protein and polypeptide sequences can be determined by first partially hydrolyzing the protein or polypeptide followed by amino acid sequencing of the fragment pieces using the chemical degradation process known as edman degradation. determine the sequence of the initial (18-amino acid) polypeptide that produces the following five partial sequences after hydrolysis and edman degradation.

You are shown 2 samples of the earthes crust . the first is denser than the second . which most likley is oceanic crust