Multiple choice

Down’s syndrome is characterised by

  1. 21 trisomy

  2. two X and one Y chromosomes

  3. 19 trisomy

  4. only one X chromosome

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

People affected with Down’s syndrome have 21 trisomy (an extra chromosome number 21). So, their chromosome count is 47 (45 + XX in females and 45 + XY in males).