After every decennial census, the districts of the House of Representatives, State Legislatures, and other representative bodies must be redrawn to reflect changes in population in the intervening ten years. This practice is called?

This practice is called redistricting.

Explanation:

In the United States, districts are geographical areas inside which eligible residents vote to elect their representatives. According to Federal law, every ten years, districts must be redrawn to reflect changes in population. The purpose is to prevent districts from having unequal populations. Redistricting can also happen in response to legal changes in the existing districts.