Final answer:
To maintain life in a closed system with only sunlight, option (A) using photosynthesis to generate energy from sunlight and recycle waste is correct. This process involves converting carbon dioxide and water into usable carbohydrates and oxygen.
Step-by-step explanation:
In order to keep organisms alive in a closed system where only sunlight is allowed in, the best strategy would be to use photosynthesis to convert sunlight into energy and recycle waste products. This is option (A) in the provided choices. Photosynthesis is a critical process that uses solar energy to change carbon dioxide and water into energy-storing carbohydrates such as glucose. In this process, oxygen is released as a byproduct. Autotrophs like plants, algae, and some bacteria can perform photosynthesis, which not only sustains their own life but also supports the lives of other organisms that depend on them for food and oxygen.
All living things access energy by breaking down carbohydrate molecules, and through photosynthesis, they create these molecules from sunlight. The cycle of photosynthesis and cellular respiration helps convert the energy from the sun into forms that other organisms can use, and these processes are essential for the maintenance of life on Earth. Hence, a closed system reliant on sunlight for energy would recycle matter within the system through these biological processes.