Answer :
The question is incomplete but assuming that the person is suffering from Down syndrome and is not able to understand the meaning of 47, XY, +21.
Answer:
2. There is an extra chromosome in the 21st pair and XY refers to gender
Explanation:
In humans, the normal number of pairs of a chromosome is 23 which means there are 46 chromosomes. Sometimes, non-disjunction during gamete formation creates or subtracts an additional copy of chromosomes as a result of which the gametes possess an extra copy of the chromosome.
In the given question, the same condition has been observed that is the person has 47, XY, +21 which is known as the Down syndrome.
The 47, XY, +21 in simple terms can be understood in the following way:
1. 47: Shows that there is one extra copy of chromosome
2. +21: means that the extra copy is of 21st pair of chromosome
3. XY: is a chromosome pair that determines the gender.
Thus, the selected option is correct.