Test center: the essence and significance of chemical synthesis photosynthesis Special topic: analysis: autotrophs refer to organisms that can transform inorganic substances into organic substances for their own growth and development. According to the different energy sources used, they can be divided into light energy autotrophy and chemical energy autotrophy. A, nitrifying bacteria belong to chemoautotrophic organisms, and A is wrong; B, cyanobacteria belong to photoautotrophic organisms, and B is wrong; C, green plants belong to photoautotrophic organisms, and C is wrong; D Flammulina velutipes can't make organic matter, but can only use ready-made organic matter, which belongs to heterotrophic bacteria. D is correct. Therefore, choose: D. Comments: The knowledge points of this question are the types of assimilation and related concepts, and the understanding of assimilation types and the formation of internal relations between knowledge points are the focus of this question.