What term describes the presence of cells in diploid organisms that contain multiples of the 2n chromosome set?

Explanation

Endopolyploidy refers to the condition where cells within a diploid organism have multiple copies of the entire 2n genome. This differs from allopolyploidy and amphidiploidy, which involve hybridization and chromosome doubling between species, while aneuploidy involves changes in chromosome number that are not exact multiples of the haploid set.