What is the main basis of difference between autotrophic and heterotrophic nutrition?

Correct answer: Whether food is made or taken from outside

The governing concept is the source and method of obtaining food. Autotrophic organisms, such as green plants, manufacture organic food from inorganic raw materials, usually using light energy, carbon dioxide, and water. Heterotrophic organisms cannot synthesize sufficient food from these materials and obtain it from other organisms or their products. Thus option A states the real distinction; blood colour, body size, and movement speed are unrelated characteristics.