Correct Answer: B. Sunlight
Detail about MCQs
The primary source of energy in most ecosystems is sunlight. Sunlight is captured by photosynthetic organisms, such as plants, algae, and some bacteria, through the process of photosynthesis. These organisms convert solar energy into chemical energy stored in organic compounds, such as glucose. This energy then flows through the ecosystem as these organisms are consumed by other organisms, forming the basis of the food chain. While ATP is a molecule that carries energy within cells, it is not the ultimate source of energy in ecosystems; instead, it is produced through processes like cellular respiration. DNA and RNA are genetic materials and not sources of energy in the context of ecosystem dynamics.