10 most extreme places on Earth. A unicellular organism is any life form that consists of just a single cell. This group includes most life on Earth, with bacteria serving as the majority. The main groups of single celled life are bacteria, archaea (both prokaryotes), and the eukaryota (eukaryotes).
A hero (masculine) or heroine (feminine) is a person or main character of a literary work who, in the face of danger, combats adversity through impressive feats of ingenuity, bravery or strength, often sacrificing his or her own personal concerns for some greater good.
Merriam Webster's definition of the term hero can be broken down into three categorie: 1  a mythological or legendary figure, later expanded to include principal male characters in dramatic works*. 2  one admired for his great courage or noble qualities. 3  an object of extreme admiration and devotion..