Autotrophic nutrition is a process whereby an organism obtains food
Autotrophic nutrition is a process whereby an organism obtains food by synthesizing simple substances using energy. In autotrophic nutrition, an organism is able to produce its own food using simple inorganic substances, such as carbon dioxide and water, and an external energy source, such as sunlight or chemical reactions. This process is called photosynthesis in plants and some bacteria, and chemosynthesis in other bacteria. Through this process, autotrophs are able to create complex organic molecules, such as carbohydrates, lipids, and proteins, that they use as a source of energy and building blocks for their cells. Autotrophic nutrition is different from heterotrophic nutrition, where an organism obtains food by consuming other living or dead organisms. Therefore, based on the given options, the correct answer is by synthesizing simple substances using energy.