From a historical point of view, genetics is a young science. The principles that govern inheritance of traits by one generation from another were described (and promptly lost) less than 150 years ago. Around the turn of the 20th century, the laws of inheritance were rediscovered, an event that transformed biology forever. But even then, the importance of the star of the genetics show, DNA, wasn’t really understood until the 1950’s.Now, technology is helping geneticists push the envelope of knowledge every day.a. Argument; conclusion: The principles that govern ... less than 150 years ago.b. Argument; conclusion: From a historical point of view, genetics is a young science.c. Nonargument.d. Argument; conclusion: Around the turn of the 20th century ... biology forever.e. Argument; conclusion: Now, technology is helping geneticists ... every day.

An argumentative text or essay is one that proffers some premises which are then followed by a conclusion. It follows a logical order where the premises offer reasons why the conclusion should be accepted as true. Sometimes. however, the conclusion can come before the premises. The writer of this text wants us to believe that genetics is a young science. This is the conclusion. He then goes on to provide historical proof or statements of facts that support this conclusion.

So the excerpt is not just a narrative of the origin and growth of the study of genetics over time and its condition today. It is an argument to support the fact that genetics is a young science.