Define autotrophic nutrition.

Autotrophic nutrition is the mode of nutrition in which organisms prepare their own food from simple inorganic substances using an external source of energy, usually sunlight.

In this process, organisms such as green plants, algae, and some bacteria use carbon dioxide and water to synthesize food in the form of glucose through photosynthesis. Chlorophyll present in these organisms helps in trapping sunlight, which provides the energy required for this process.

Autotrophic nutrition forms the basis of all food chains, as autotrophs act as primary producers and supply energy to other organisms.