The oxygen in Earth's atmosphere
A)was manufactured inside stars.
B)was added to the atmosphere by plant life.
C)has grown more abundant since the origin of Earth.
D)was manufactured inside stars, was added to the atmosphere by plant life, and has grown more abundant since the origin of Earth.
E)None of the other choices are correct.

Question

Quizplus · Accepted Answer

Oxygen in Earth's atmosphere was originally manufactured inside stars through nuclear fusion. It was then added to the atmosphere by plant life through photosynthesis. Over time, the amount of oxygen in the atmosphere has increased through geological processes like the weathering of rocks and the formation of new terrestrial and marine environments. Therefore, the correct answer is D as it includes all three processes.

The Oxygen in Earth's Atmosphere