In a food chain, which organism is typically the primary source of energy for the ecosystem?

• A. Consumers
• B. Producers
• C. Decomposers
• D. Apex predators

Answer: (B)

Energy flow in ecosystems begins with producers. They capture energy from the sun (through photosynthesis) or, in some cases, from chemical energy (chemosynthesis) and convert it into chemical energy stored in sugars. This stored energy forms the base of the food chain, supplying the energy that all other organisms need as they eat producers and then each other. Decomposers break down dead material and recycle nutrients, but they don’t provide the initial energy input—they rely on energy that already entered the ecosystem. Apex predators are high-level consumers that rely on energy that originally came from producers, not the source itself.