Autotrophic nutrition is the process by which certain organisms produce their own food using light energy, water, carbon dioxide, and minerals. The necessary conditions for autotrophic nutrition are:

Necessary Conditions
1. *Light energy*: Autotrophic organisms require light energy from the sun to power photosynthesis.
2. *Water*: Water is essential for photosynthesis and is used to convert carbon dioxide into glucose.
3. *Carbon dioxide*: Autotrophic organisms use carbon dioxide from the atmosphere to produce glucose.
4. *Minerals*: Essential minerals like nitrogen, phosphorus, and potassium are necessary for autotrophic nutrition.
5. *Chlorophyll*: Autotrophic organisms contain chlorophyll, a green pigment that absorbs light energy.

By-Products of Autotrophic Nutrition
The by-products of autotrophic nutrition are:

1. *Glucose*: Autotrophic organisms produce glucose, a type of sugar that serves as energy storage.
2. *Oxygen*: Oxygen is released as a by-product of photosynthesis, which is essential for the survival of most living organisms.

Examples of Autotrophic Organisms
Examples of autotrophic organisms include:

1. *Plants*: Plants are the most common autotrophic organisms, using photosynthesis to produce glucose.
2. *Algae*: Algae are simple aquatic plants that use photosynthesis to produce glucose.
3. *Cyanobacteria*: Cyanobacteria are bacteria that use photosynthesis to produce glucose.

Autotrophic nutrition, specifically through photosynthesis, requires sunlight, chlorophyll, carbon dioxide, and water. The byproducts of this process are carbohydrates (food for the plant) and oxygen.
Elaboration:
Sunlight: Provides the energy needed to convert water and carbon dioxide into glucose (a type of sugar).
Chlorophyll: A pigment that absorbs sunlight, allowing the process to begin.
Carbon dioxide: Absorbed from the atmosphere through tiny pores in leaves called stomata.
Water: Absorbed from the soil through the roots and transported to the leaves.
Byproducts:
Carbohydrates (glucose): The main product, which the plant uses for energy and storage.
Oxygen: A byproduct released into the atmosphere.