Answer:
The correct option is d) 21 has an extra chromosome
Explanation:
The complete array of chromosomes that an individual possesses is known as the karyotype of the individual. Humans have 46 chromosomes which make up 23 pairs.
In the karyotype shown in the picture, the 21st pair has an extra chromosome. Such a condition is known as Down's Syndrome. In such a person, the mental ability of the person is influenced and he usually suffers from mental disabilities. The facial features of such a person also are different.