In world geography, what is meant by the International Date Line with respect to longitude on the globe?

Introduction / Context:
Time and date on the earth are related to the rotation of the planet and to the system of longitudes. To keep dates consistent when travelling around the world, a special imaginary line called the International Date Line is used. Understanding its approximate location is an essential part of basic world geography and is commonly tested in competitive exams.

Given Data / Assumptions:

• We are asked about the International Date Line as it relates to longitude.
• Options include the equator, zero degrees longitude, ninety degrees longitude, and one hundred eighty degrees longitude.
• We assume the usual convention that time zones are based on the prime meridian and the opposite meridian.

Concept / Approach:
The International Date Line is an imaginary line on the surface of the earth that roughly follows the one hundred eighty degree meridian, which is directly opposite the prime meridian of zero degrees longitude. When a traveller crosses this line from west to east or east to west, the calendar date changes by one day. Because the line passes through the Pacific Ocean, it is not a perfectly straight meridian; it zigzags around some islands to keep countries within single time zones and dates. However, in exam questions, it is generally described as corresponding to one hundred eighty degrees longitude.

Step-by-Step Solution:
Step 1: Recall that the prime meridian at Greenwich is zero degrees longitude and is the reference for world time zones.Step 2: Understand that after one hundred eighty degrees of rotation, you reach the opposite side of the globe, where the date must be adjusted.Step 3: Remember that the International Date Line is chosen to lie mainly along this opposite meridian, one hundred eighty degrees longitude.Step 4: Note that minor deviations for political and practical reasons do not change its basic description.Step 5: Therefore identify one hundred eighty degrees longitude as the correct answer.

Verification / Alternative check:
Any world map that shows lines of longitude and the International Date Line will display it roughly in the mid Pacific region, opposite Greenwich. The annotation often directly states that it is near one hundred eighty degrees longitude. Time zone diagrams also clearly mark the shift in date at this meridian, which confirms its role as the International Date Line.

Why Other Options Are Wrong:
The equator: This is zero degrees latitude, separating the northern and southern hemispheres, not a longitude line.Zero degrees longitude: This is the prime meridian passing through Greenwich, used as a reference for world time, not the date line.Ninety degrees longitude: This is a meridian but has no special global function regarding date changes.

Common Pitfalls:
Students occasionally confuse the equator and prime meridian or think of the date line as a straight meridian without accounting for practical shifts. Others may wrongly assume zero degrees longitude because they associate all time systems with Greenwich. A helpful memory trick is that the International Date Line is opposite the prime meridian, so its longitude is one hundred eighty degrees.

Final Answer:
The International Date Line is approximately located along one hundred eighty degrees longitude on the globe.