What is the name of the enzyme that separates the two chains of the parent dna

At the primer segment, the enzyme DNA polymerase polymerizes the original DNA strand. It works at the area where DNA is unwinding, called the replication fork. The nucleotides are polymerized starting at one end of the nucleotide chain, and synthesis proceeds in only one direction of the strand (the “leading” strand).

answer; polycythemia is the correct answer;

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .