Final answer:
The federal census occurs every ten years in years that end in zero, as mandated by the U.S. Constitution, to help in the reapportionment of congressional representatives and the fair distribution of federal resources.
Step-by-step explanation:
The federal census is always taken on years that end in the number zero. This decennial census is a constitutional requirement, crucial for reapportioning representatives among the states, and determining how federal resources are distributed. The counts are used to readjust the boundaries of the congressional districts, a process known as reapportionment. The U.S. Constitution mandates that this enumeration occurs every ten years to ensure each state is fairly represented in Congress based on its population.
The census not only counts the number of people but also gathers information about housing, businesses, and other demographic data. The most recent example is the 2020 census, following the previous one conducted in 2010, and so on, each occurring in a year ending in zero. This count is essential for the government to adjust and provide services accordingly.