Multiple choice

Which of the following processes do not use oxygen?

  1. Combustion

  2. Respiration

  3. Formation of oxides

  4. Photosynthesis

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Photosynthesis does not use oxygen - in fact, it produces oxygen as a byproduct while consuming carbon dioxide. Combustion, respiration, and oxide formation all require oxygen to occur. Photosynthesis is the only process listed that is oxygen-independent and actually generates oxygen.