A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. A Mutagen is an agent of substance that can bring about a permanent alteration to the physical composition of a DNA gene such that the genetic message is changed.
1 Objective can be defined as not being influenced by personal feelings or opinions. 2  Subjective can be defined as based on personal opinion.  A statement that is completely unbiased is objective whereas a statement that is characterized by the thoughts and the views of the speaker is subjective.
An objective, on the other hand, is a very direct thing that can be achieved, and which can be measured. An objective might be to memorize the periodic table of elements by the exam next week. This gives you a definite time frame and a specific thing that has to be accomplished, and it gives you a fairly simple idea of how it has to be done.