The biological species concept is A)applicable to all forms of life, past and present.
B)easy to apply to all present sexually reproducing organisms, but harder to apply to asexual organisms and fossils.
C)applicable to all present life forms, but not to fossil organisms whose reproductive behavior cannot be observed.
D)sometimes difficult to put into practice even for present sexual organisms, and useless for asexual organisms and fossils.

d. the weight of the book

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."

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.