Living organisms can be divided into two groups on the basis of their mode of nutrition.
In this mode of nutrition in which organisms can prepare their own food from inorganic raw material taken from their surroundings are known as autotrophic organisms.
Autotrophs are photosynthetic like plants, algae and some bacteria etc.
In this mode of nutrition organism which are unable to prepare their own food from Simple inorganic compounds are known as heterotrophic organisms.
Most bacteria, fungi and animals have heterotrophic modes of nutrition.