What is the term for the representation and distribution of representatives in Congress based on population changes?

Reapportionment is the correct term for the process that involves the allocation of congressional seats to states based on changes in population, as determined by the decennial census. After each census, Congress may redistribute the number of seats each state holds in the House of Representatives to reflect shifts in population. This ensures that representation in Congress remains equitable and reflective of the current demographic distribution across the country.

While redistricting is a related process that involves drawing the boundaries of electoral districts, it occurs after reapportionment and is focused on how to shape district lines within each state. Districting and constituency realignment involve concepts of organizing and aligning political boundaries or changing affiliations among constituents but do not specifically pertain to the redistribution of representatives based on population data. This distinction is crucial for understanding legislative representation and its dependence on demographic changes.