Biology STAAR Practice Test 2026 - Free State of Texas Assessments of Academic Readiness Practice Questions and Study Guide

Plants play a crucial role in the carbon-oxygen cycle primarily through photosynthesis. During this process, they consume carbon dioxide from the atmosphere and, using sunlight, convert it into glucose while releasing oxygen as a byproduct. This transformation is essential for maintaining the balance of gases in the atmosphere and supports life on Earth.

By consuming carbon dioxide, plants help to reduce the amount of this greenhouse gas, thereby mitigating climate change. At the same time, the oxygen they generate is vital for the respiration of most living organisms, which depend on oxygen for energy production.

In summary, plants are not only responsible for consuming carbon dioxide but also for generating glucose, which serves as a primary energy source for many organisms, along with releasing oxygen that supports aerobic life. This combined function highlights their importance in the carbon-oxygen cycle, which is effectively encapsulated in the correct choice.