Final answer:
The International Date Line generally does not follow the 49th parallel. Crossing the date line from west to east advances the time by decreasing the date, while crossing from east to west increases the date by one day. It is an arbitrary line on the surface of Earth near longitude 180° across which the date changes by one day.
Step-by-step explanation:
The International Date Line generally does not follow the 49th parallel. It is an arbitrary line on the surface of Earth near longitude 180° across which the date changes by one day. Crossing the date line from west to east advances the time by decreasing the date, while crossing from east to west increases the date by one day.