the science calorie (little c) is a measure of heat energy the food calorie (big C) is a measure of energy that we burn, but it is equal to 1,000 science calories so 1 big C is equal to 1,000 little c's.
Protists are a group made up of protozoa, unicellular algae, and slime molds. We will concentrate on the animal portion of this group: the protozoa (proto = first, zoa = animals).
Protozoa are microscopic, single-celled organisms that sometimes group together into colonies. There are both autotrophic and heterotrophic types of protozoa. Unlike bacteria and fungi, which absorb dissolved organic compounds from their environment, heterotrophic protozoa (such as the amoebas and Paramecium) consume other organisms such as algae, bacteria, or other protists.