The accumulation of free oxygen in the atmosphere
A) was a result of the accumulation of a by-product of a type of photosynthesis.
B) prevented the further spontaneous generation of life.
C) provided the opportunity to extract more energy through aerobic respiration.
D) did not occur immediately after the earth was formed.
E) did all of these.

Question

Quizplus · Accepted Answer

- A) True, the accumulation of free oxygen was a result of the accumulation of a by-product of a type of photosynthesis called oxygenic photosynthesis.
- B) True, the presence of free oxygen in the atmosphere prevented the further spontaneous generation of life that relied on anaerobic metabolisms.
- C) True, the accumulation of free oxygen in the atmosphere provided the opportunity for organisms to extract more energy through aerobic respiration, which is more efficient than anaerobic respiration and fermentation.
- D) True, the accumulation of free oxygen did not occur immediately after the earth was formed, but it took billions of years for photosynthetic organisms to evolve and for the atmospheric oxygen to accumulate to significant levels.
Therefore, since all of these statements are true, the best choice is E.

The Accumulation of Free Oxygen in the Atmosphere