Eubacteria can be both autotrophs and heterotrophs. Autotrophic eubacteria produce their own food through processes like photosynthesis or chemosynthesis. For example, cyanobacteria use sunlight to convert carbon dioxide and water into glucose and oxygen.
On the other hand, heterotrophic eubacteria rely on organic substances for nutrition. They obtain energy by breaking down complex organic compounds from their environment. Many eubacteria fall into this category, including those that decompose organic matter or live as parasites.
In summary, eubacteria exhibit diverse nutritional strategies, with some being autotrophs and others being heterotrophs.