Concept:Autotrophic nutrition is the process by which an organism produces its own food from simple inorganic substances using energy.Explanation:Autotrophs like green plants make organic food such as glucose.They use simple raw materials like carbon dioxide and water for this process.Energy is required to build food from these simple substances.This energy comes from sunlight in photosynthesis or from chemical reactions in chemosynthesis.Hence, the organism does not depend on other organisms for ready-made food.Answer:B. by synthesizing simple substances using energy