RAS question
The International Date Line approximately follows:
Correct answer: (D) 180° longitude through the Pacific Ocean, with zigzags to avoid land.
The International Date Line roughly follows 180 degrees longitude through the mid-Pacific Ocean, with zigzags around political borders and land-linked island groups.
Explanation
The International Date Line is best understood as the calendar boundary near 180 degrees longitude. NOAA's National Ocean Service states that it passes through the mid-Pacific Ocean and roughly follows a north-south 180 degrees longitude line, halfway around the world from the Prime Meridian at Greenwich. That is why option D is right: it is a longitude-based line, not a latitude such as the Equator or Tropic of Cancer. The line is not perfectly straight because countries can choose the dates they observe, so it bends around political borders, including eastern Russia and Alaska's Aleutian Islands, to avoid splitting connected territories across two calendar dates. Crossing it westward moves the calendar one day ahead; crossing eastward moves it one day back.
Why the other options are wrong
- (A) The Equator is 0 degrees latitude, while the International Date Line is tied to longitude near 180 degrees.
- (B) The Tropic of Cancer is also a latitude line, so it cannot describe the north-south date boundary near 180 degrees longitude.
- (C) 0 degrees longitude is the Prime Meridian at Greenwich, whereas the International Date Line lies roughly halfway around the world from it.
Concept
This tests the world geography concept of latitude-longitude grids and time reckoning. RAS repeatedly uses such questions because map fundamentals explain time zones, calendar change and the location of major reference lines.