HOW to choose a model organism? It depends on what question is being asked. When studying fundamental issues of molecular bIologY, sImpler unicellular organisms or viruses are convenient, For developmental questions, more complicated organisms should be usedHOW to choose a model organism? It depends on what question is being asked. When studying fundamental issues of molecular biology, simpler unicellular organisms or viruses are convenient. For developmental questions, more complicated organisms should be used