(Primary Science) Are plants the only organisms that make food on their own?

When I was a primary school student, my teachers often said "green plants" instead of "plants" because we used to believe mushrooms are "non-green plants". Today we understand that mushrooms are of a totally different class of organisms called fungi, not plants. Still I hear people saying "green plants" these days instead of simply "plants" probably to emphasize to students that these organisms contain chlorophyll, the green pigment, that helps absorb sunlight and photosynthesize. We can generalize that all plants make food on their own although there are exceptions.

Plants contain chlorophyll which helps to photosynthesise... 

But plants aren't the only organisms that can make food. Other photosynthetic organisms include algae (which are classed under Protista) and phytoplankton (which are tiny photosynthetic organisms of various classes that drift in water bodies such as seas and lakes).

Algae and phytoplankton photosynthesise too...