What is the main energy source producers use to make their own food?

• A. Soil nutrients
• B. Water
• C. Light energy
• D. Chemical energy from rocks

Answer: (C)

Light energy from the sun powers photosynthesis, the process by which producers make their own food. Chlorophyll in the plant absorbs light and uses that energy to drive reactions that combine carbon dioxide from the air with water from the soil to build glucose, a sugar that stores chemical energy. This stored energy fuels growth and metabolic activities and is passed to other organisms when they eat the plants. Soil nutrients supply minerals essential for growth but don’t provide the energy themselves. Water is needed for the reactions but isn’t the energy source. Chemical energy from rocks describes chemosynthesis used by some organisms in special environments, not the common method for most producers.