Answer: Option C) carbon source
Step-by-step explanation:
The type of Carbon source is the distinction between heterotroph or autotroph. As autotrophs like green plants generate their food (glucose) from simple inorganic molecules like carbon dioxide (CO2) in the atmosphere, while heterotroph like man utilize carbon in carbohydrates such as starch that have been stored in the tissues of autotrophs.
Thus, the type of carbon source utilized distinguished heterotroph and autotrophs