3. What is an acid?
Idk

an acid is a chemical substance that neutralizes alkalis dissolves some metals and turns litmus red typically a corrosive or sour-tasting liquid of this kind

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."