Final answer:
Reapportionment is the process of redistributing representation in the legislative bodies according to the latest U.S. Census population data, while redistricting is drawing new district boundaries based on this data to ensure equal representation.
Step-by-step explanation:
The redistribution of representation based on the decennial recounting of residents is called reapportionment. This process is essential to maintain equal representation in the legislative bodies of government by adjusting the number of seats each state has in the House of Representatives according to the population data collected by the U.S. Census.
Redistricting is the related process where new district boundaries are drawn to ensure districts have nearly equal populations and to meet Voting Rights Act requirements, which prevent districts from being devised in ways that diminish the voting strength of minorities. However, this process can lead to gerrymandering when district lines are drawn to favor a particular political group or party, which can sometimes lead to legal challenges.