Oxygen makes up almost 21 percent of our present atmosphere. It is essential to modern life for two reasons. First, oxygen is what we must inhale so that our bodies can 'burn' (oxidize) food, releasing energy to our cells. Second, we depend on oxygen for protection from the ultraviolet radiation from the sun that constantly bombards our planet. Harold V. Thurman, Essentials of Oceanography, 5th. ed.
A) Argument; conclusion: Oxygen is essential to modern life.
B) Argument; conclusion: Oxygen makes up almost 21 percent ... atmosphere.
C) Argument; conclusion: We depend on oxygen ... bombards our planet.
D) Argument; conclusion: Oxygen is what we must inhale ... energy to our cells.
E) Nonargument.

Question

Quizplus · Accepted Answer

The passage presents reasons why oxygen is essential to modern life, making it an argument with the conclusion that oxygen is essential for these reasons.

Oxygen Makes Up Almost 21 Percent of Our Present Atmosphere