According to the concept of autotrophic: organisms that can synthesize inorganic substances into their own organic substances belong to autotrophic organisms. The concept of heterotrophy: You can only take in organic matter from the outside to synthesize your own organic matter. The key difference between inorganic matter and organic matter is whether it is inorganic carbon or organic carbon.

Therefore, from the point of view of autotrophic carbon source, autotrophic carbon source is inorganic carbon source and heterotrophic carbon source is organic carbon source.

Regardless of nitrogen source. For example, Nepenthes preys on insects, but only to supplement nitrogen source, carbon source or carbon dioxide, so it is autotrophic. Many microorganisms can use inorganic nitrogen, such as nitrogen-fixing microorganisms, but there are still differences.

For example:

1.( 1) photoautotrophic: green plants, photosynthetic bacteria (2) autotrophic: nitrifying bacteria, sulfur bacteria, iron bacteria.

2. Heterotrophic type: people, animals, most fungi and most bacteria.