Which statement correctly describes respiration?

• A. Carbs and O2 are produced from sugars
• B. Glucose is synthesized from carbon dioxide during respiration
• C. Water is used to generate energy without releasing CO2
• D. Carbs and O2 break down to produce energy, water, and CO2

Answer: (D)

The idea being tested is how cellular respiration uses glucose and oxygen to release energy. In respiration, carbohydrates are oxidized with oxygen to produce energy in the form of ATP, with water and carbon dioxide as byproducts. The statement that carbohydrates and oxygen break down to produce energy, water, and CO2 fits this exactly, describing the core outcome of aerobic cellular respiration: energy captured as ATP plus waste products of water and carbon dioxide.

The other statements misrepresent the process. Producing sugars and oxygen from carbohydrates describes photosynthesis, not respiration. Glucose being synthesized from carbon dioxide during respiration is also a reversal of the actual process. Saying water is used to generate energy without releasing CO2 ignores that CO2 is a normal byproduct of respiration, and the typical pathway releases CO2.