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.
Tragic Hero. Definition of Tragic Hero. The term hero is derived from a Greek word that means a person who faces adversity, or demonstrates courage in the face of danger. However, sometimes he faces downfall as well. When a hero confronts downfall, he is recognized as a tragic hero or protagonist.