Our nostrils has hair and mucous. What is the need to have them in our nasal cavity?

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;

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."