How have the factors that trigger an asthma attack changed since the 1900s? As a researcher, how would you put together the clues given here to explain the emerging epidemic?

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."