While blizzards often feature extreme cold and heavy snow, there are actually no temperature or snow depth requirements for a storm to qualify as a blizzard. Occasionally, blizzard conditions will present when there is no precipitation.
Definition. 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.efinition. 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 A harmful, or deleterious, mutation decreases the fitness of the organism.  A beneficial, or advantageous mutation increases the fitness of the organism. Mutations that promotes traits that are desirable, are also called beneficial.