Which statement best describes cyanobacteria's energy production and waste product?

Which statement best describes cyanobacteria's energy production and waste product?

• A. Use CO2 for energy and release oxygen
• B. Use O2 for energy and release CO2
• C. Use glucose for energy and release methane
• D. Use water for energy and release hydrogen

Answer: (A)

Cyanobacteria perform oxygenic photosynthesis, using light energy to drive the transformation of carbon dioxide and water into sugars. The energy comes from sunlight, while carbon dioxide provides the carbon skeleton for these sugars. Water donates electrons and is split, releasing oxygen gas as a byproduct. So the statement that CO2 is used and oxygen is released best describes what cyanobacteria do. The other options don’t fit this process: they imply using oxygen as an energy source, producing methane, or releasing hydrogen, which aren’t how cyanobacteria operate.

Cyanobacteria perform oxygenic photosynthesis, using light energy to drive the transformation of carbon dioxide and water into sugars. The energy comes from sunlight, while carbon dioxide provides the carbon skeleton for these sugars. Water donates electrons and is split, releasing oxygen gas as a byproduct. So the statement that CO2 is used and oxygen is released best describes what cyanobacteria do. The other options don’t fit this process: they imply using oxygen as an energy source, producing methane, or releasing hydrogen, which aren’t how cyanobacteria operate.