What is a major distinction between the hydrogen chemolithotrophs and many sulfur chemolithotrophs and nitrfying bacteria?

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

How far down have geologists drilled holes ? (science) a: 3.8 km b: 12 km c: 100 m d: 1200 km

The primary organisms involved in the process bacteria and fungi.