Question

What will be Q and R?

	Q	R
A.	XY	XX
B.	XX	XY
C.	XY	XY
D.	XX	XX

I. A
II. B
III. C
IV. D

Answer 1

Hint: The biological system that determines the development of sexual characteristics in an organism is called as sex – determination. In addition to it, human females have two same kind of sex chromosome whereas, human males have two different chromosomes. The probability of giving birth to son and daughter is fifty percent each. The chromosome transferred by father determines the sex of an offspring.

Complete step by step answer: Sex determination can be defined as a biological system in which development of sexual characteristics in an organism can be determined. Offsprings are produced by sexual reproduction with each organism having two sets of chromosomes. Sexual morphology can be specified as males and females have different alleles or even different genes. Differences in chromosome help in determination of sexes of an organism. XY, ZW, XO, ZO chromosomes, or haplodiploidy are the different combination of chromosomes which help in determination of sex. XX/YY sex chromosomes as found in most of the organisms including humans. In humans the male individual consists of two different sets of chromosomes that are XY and in females they have two same sets of chromosomes that are XX.
Hence, the correct answer is option II: XX XY is the correct answer as per the condition given daughter and son. Also, the mother consists of the same chromosome XX and son consists of two different sets of chromosomes XY.

Note: Some species of various plants and fish do not have a fixed sex, and instead they go through life cycles which leads to the change in sex based on genetic cues during corresponding life stages of their type.