The specific cause of Parkinsonâs is unknown; however, medical experts believe the symptoms are related to a chemical imbalance in the brain caused by brain-cell death. Parkinson's disease is chronic (persists over a long period of time), and progressive (symptoms grow worse over time).arkinson's disease (or, simply, Parkinson's or PD) is the most common form of parkinsonism, a group of motor system disorders.
Quick Answer. Non-mandatory ZIP codes were introduced to the United States in 1963. Robert Moon, a postal inspector with the United States Postal Service, proposed the ZIP code system as early as 1944. Continue Reading.
zip code. A code which was established by the United States Postal Service, for the purposes of identifying a location and routing the mail to that location. A zip code was originally 5 digits long, and now has been expanded to 9 digits for more detailed identification. The 5 digit zip code is still sufficient for sending all items of mail; the 9 digit zip code is used primarily by businesses as they sometimes get a discount for doing so.