Vectors are: a. dna molecules used to carry foreign dna fragments into bacteria or other cells b. dna molecules that can be joined with dna fragments that are to be cloned c. rna molecules that can be joined with dna fragments that are to be cloned d. large eukaryotic chromosomes

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.