If galaxies contain 1 hundred billion stars and there are 1 hundred billion galaxies and 1 in 5 low mass stars like the sun have planets like Earth in the habitable zone and 89% of all stars are low mass like the Earth what is the number of planets that exist in the Universe that are in the habitable zones of their stars?

roughly 178,000,000,000,000,000,000,000 also put as 1.78 x 10^21

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."