Why are Plants are called producers because they?
They turn sunlight into food.
Producers are green plants. And these plants are green because of a pigment called 'Chlorophyll'. This pigment with the help of carbondioxide from air and sunlight creates food for the plant by a process call 'Photosynthesis'. All other living things in the food chain survive because of this natural ability (Photosynthesis) of plants.
Plants are called producers because they are able to prepare energy and produce carbon for themselves using inorganic substances like sunlight, water and carbon dioxide. They are the one that prepare their own food and all other organisms are either directly or indirectly dependent on them for food.
Most bacteria and fungi are not known as producers because they do not produce their food in processes like photosynthesis. Cynanobacteria are a type of bacteria that conducts photosynthesis which is why they are producers. Many forms of bacteria carry out chemosynthesis which makes them producers. Some fungi are called radioatrophs which also make them producers. Yet for the most part plants are producers.