You are presented with the question "What do ecosystems in nature need an influx of to remain feasible?" and the following answer choices: - Continuous nuclear energy. - Natural lipids and proteins. - Energy. - rain - water - Energy - oxygen - Renewable Sunny Delight. Now knowing that energy enters ecosystems in the form of sunlight or chemical compounds and sunlight is the source of light in nature, choose the best answer.
A:
Energy.