Why would a scientist not consider viruses to be living organism?

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom

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."