The organisms that produced the oxygen gas in Earth's early atmosphere were
A) anaerobic eukaryotes.
B) aerobic eukaryotes.
C) photosynthetic prokaryotes.
D) aerobic prokaryotes.
E) completely unlike modern organisms.

Question

Quizplus · Accepted Answer

The organisms that produced the oxygen gas in Earth's early atmosphere were photosynthetic prokaryotes, specifically cyanobacteria. These were able to convert sunlight and carbon dioxide into oxygen through the process of photosynthesis, which gradually led to the accumulation of oxygen in the atmosphere over millions of years.

The Organisms That Produced the Oxygen Gas in Earth's Early