In microbiology the roles of mutation and selection in evolution are coming to be better understood through the use of bacterial cultures of mutant strains.
I declare that The Beatles are mutants. Prototypes of evolutionary agents sent by God, endowed with a mysterious power to create a new human species, a young race of laughing freemen.
(n.) Change; alteration, either in form or qualities.
It wasn't torpor that kept her - she was often restless to the point of irritability. She simply liked to feel that she was prevented from leaving, that she was needed.
How is it that you keep mutating and can still be the same virus?