In which sealed container would organisms be able to continuously cycle O_2 and CO_2 gases?

• A. A container with only fungi
• B. A container with only plants
• C. A container with only animals
• D. A container with both plants and animals

Answer: (D)

Verified step by step guidance

1. Understand the roles of different organisms in gas exchange: plants perform photosynthesis, taking in carbon dioxide (CO_2) and releasing oxygen (O_2), while animals and fungi perform respiration, taking in oxygen and releasing carbon dioxide.
2. Analyze a container with only fungi: fungi respire and release CO_2 but do not perform photosynthesis, so O_2 would eventually be depleted.
3. Analyze a container with only plants: plants produce O_2 during photosynthesis but also respire, consuming O_2 and releasing CO_2; however, without animals or fungi to produce CO_2, the CO_2 levels would drop, limiting photosynthesis.
4. Analyze a container with only animals: animals respire, consuming O_2 and releasing CO_2, but without plants to convert CO_2 back to O_2, oxygen would eventually run out.
5. Conclude that a container with both plants and animals allows continuous cycling of O_2 and CO_2 because plants produce oxygen for animals, and animals produce carbon dioxide for plants, maintaining a balanced gas exchange.