What parts of the environment, natural and manmade, make up a watershed?

Explanation:

The definition of watershed is

"any point on uphill from where water flows downstream wither in the form of river, stream or rain water".

From the definition we can say that watershed (either natural or man made) would me anything that is present in that area where the water flows downstream to houses, parks, and dams.

I have attached picture for better understating.

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."