Adisadvantage of using hydroelectricity is select one it is nonrenewable it is a nonrenewable resource it can disturb natural ecosystems it causes air pollution

The greenhouse effect is primarily caused by cars and trucks.

Explanation:

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."

helicase, i think thats it