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.
Nearly every story has at least one protagonist. A protagonist is a main character who generates the action of a story and engages the reader's interest and empathy. The protagonist is often the hero or heroine. For example, in the popular Divergent trilogy, the protagonist is Tris.