单选题 In many simple organisms, including bacteria and various protests, the life cycle is completed within a single generation: an organism begins with the fission of an existing individual; the new organism grows to maturity; and it then splits into two new individuals, thus completing the cycle.
【正确答案】 A
【答案解析】[解析] 这里的fission的意思是“裂开，分裂，分体”。四个选项中，A项split的意思是 “劈开，(使)裂开，分裂，分离”；B项fusion的意思是“熔化，熔解，熔合，熔接”；C项 explosion的意思是“爆发，发出，爆炸”；D项modification的意思是“更改，修改，修正”。 四个选项中，只有A项符合题意要求。