The answer is B. even if you fill out a Punnett Square there is still a possibility that it won't come out that way. for example there could be two dominant traits in a Punnett square instead of just one completely dominant trait. like BB and BB.
Environments are always changing so organisms need to adapt to survive. The organisms that survive are the ones that are fit to live in that environment, which is where survival of the fittest comes into play.
It's called merging cells. I don't understand why this is in Biology but whatever.
