Answer: A. plants
Explanation: plants begin the food chain because it is a producer, which doesn't eat other animals to get energy.
Answer:
<em>photosynthesis</em><em> is</em><em> </em><em>the</em><em> </em><em>process</em><em> </em><em>whereby</em><em> </em><em>plants</em><em> </em><em>absorb</em><em> </em><em>carbon</em><em> </em><em>dioxide</em><em> </em><em>from</em><em> the</em><em> </em><em>air</em><em> and</em><em> </em><em>release</em><em> </em><em>oxygen</em><em> </em><em>during</em><em> </em><em>respiration</em>
They are formed with the flow of air or water.
My guess would have to be hydropower, since water isn't an un natural substance