1-What event marked the start of the space age?

2-what are space shuttles used for?

its 42

i say its d?

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."

sex cells are usually half's then they find another half and make a fertilize egg