Question

The organisms that produced the oxygen gas in Earth's atmosphere in ancient times were

A. heterotrophic eukaryotes.
B. autotrophic eukaryotes.
C. autotrophic prokaryotes.
D. heterotrophic prokaryotes.
E. completely unlike modern organisms

Answer 1

Any options?

Answer 2

It's hard to keep oxygen molecules around, despite the fact that it's the third-most abundant element in the universe, forged in the superhot, superdense core of stars. That's because oxygen wants to react; it can form compounds with nearly every other element on the periodic table. So how did Earth end up with an atmosphere made up of roughly 21 percent of the stuff?

The answer is tiny organisms known as cyanobacteria, or blue-green algae. These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. In fact, all the plants on Earth incorporate symbiotic cyanobacteria (known as chloroplasts) to do their photosynthesis for them down to this day.

Answer 3

here are the choices A. heterotrophic eukaryotes.
B. autotrophic eukaryotes.
C. autotrophic prokaryotes.
D. heterotrophic prokaryotes.
E. completely unlike modern organisms

Answer 4

To produce oxygen gas, the organism must be autotrophic
In the ancient times, eukaryotes have no evolved yet, so the answer is autotrophic prokaryotes
and an example is cyanobacteria

Answer 5

Thanx a lot!