If the theory of natural selection is the survival of the fitness, and the fittest are identified as those who survive, why isn't it regarded as a tautology (a statement that is true only because of the meaning of the terms) ?

• A. The effect of traits on the fitness of an organism can be assessed independently of whether the organism indeed survives .
• B. It is regarded as a tautology - the question is based on a false assumption.
• C. There may be some statements in science that are useful even if they are not falsifiable or refutable in principle.
• D. A and C.