Monerans may be heterotrophic (saprophytes, parasites, symbionts etc.) or autotrophic (chemosynthetic like nitrifying bacteria, sulphur oxidising bacteria etc. or photosynthetic). Protists are heterotrophic organisms which may be holozoic, saprobic, parasitic, etc. Some protists are autotrophic but photosynthetic only. Fungi are heterotrophic organisms which may be symbiont, parasites or decomposers. Plants are mainly autotrophic, only some of them are partial heterotrophs.