Which condition involves extra sets of chromosomes?

• A. Monosomy
• B. Trisomy
• C. Polyploidy
• D. Nondisjunction

Answer: (C)

Having more than two complete chromosome sets defines polyploidy. In normal body cells, chromosomes come in two sets (diploid). When an organism has three or more complete sets (3n, 4n, etc.), that’s polyploidy—a situation where the entire genome is duplicated or triplicated, not just individual chromosomes. This is common in many plants and can lead to larger cell size and changes in fertility.

Monosomy means a missing chromosome (one copy instead of two of a particular chromosome). Trisomy means an extra copy of a single chromosome (three copies of one chromosome, not entire extra sets). Nondisjunction is the error that can cause such numerical abnormalities by failing to separate chromosomes during cell division. The question specifically asks for extra sets of chromosomes, which is polyploidy.