CNA Practice Test
Mental health and dementiaQuestion 682 of 1700

Down syndrome is also called "Trisomy 21." What does that mean?

  1. One missing copy of chromosome 21
  2. Twenty-one extra genes in each cell
  3. The condition starting at age 21
  4. An extra copy of chromosome 21 in the cells
Show answer

Correct answer: An extra copy of chromosome 21 in the cells

Trisomy means an extra copy of a chromosome. Here it is chromosome 21.

Source: Nursing Assistant (Reuter), 10.3: Caring for Clients With Developmental Disorders

Practice mental health and dementia

Questions last reviewed: 18 October 2026