The three modes of heterotrophic nutrition are:
(i) To break down of the food material outside the body and then absorb it. For example, bread moulds, yeasts and mushroom.
(ii) To take in whole material and break it down inside the body. For example, animals eating grass, fruits, insects, fish etc.
(iii) Parasitic nutrition - To derive nutrition from other plants or animals without killing them. For example, custuta (amar-bel), orchids, leeches, tape-worms etc.