DIVE Integrated Chemistry and Physics (ICP) Quarterly Exam 3 Practice 2026 - Free ICP Practice Questions and Study Guide.

The correct answer is oxygen, which is produced during the process of photosynthesis. During photosynthesis, plants, algae, and some bacteria convert carbon dioxide and water into glucose and oxygen using sunlight as energy. The overall equation for this process can be summarized as:

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

In this equation, six molecules of carbon dioxide and six molecules of water react to produce one molecule of glucose and six molecules of oxygen. The oxygen produced is released into the atmosphere, which is essential for the survival of aerobic organisms, including humans.

The other gases listed do not play a direct role as a product of photosynthesis. Carbon dioxide is a reactant, while nitrogen and hydrogen are not products of this specific biological process and do not directly contribute to the photosynthetic pathway in plants. Thus, oxygen stands out as the significant byproduct that makes photosynthesis crucial not only for plant life but also for life on Earth as a whole.