This human karyotype is unusual because chromosome set
a. 5 has chromosomes of different shapes
b. 10 is missing genetic material
c. 14 has enlarged centromeres
d. 21 has an extra chromosome

This human karyotype is unusual because chromosome set 21 has an extra chromosome (option d).

In conclusion, this human karyotype is unusual because chromosome set 21 has an extra chromosome (option d).

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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.