Question

In human sex determination, the key factor is
a. Y chromosome
b. X chromosome
c. Both A and B
d. None of the above

Answer 1

Hint: Sexual differentiation in humans is the procedure of development of sex variations in humans. It is defined as the development of phenotypic structures consequent to the motion of hormones produced following gonadal will power. Sexual differentiation includes improvement of various genitalia and the inner genital tracts and body hair plays a position in gender identification.

Complete answer:
• All woman eggs convey one X chromosome; consequently, it's far the chromosome carried inside the sperm that determines the sex of the embryo for the time being of the idea.
• If the egg is fertilized with the aid of a sperm with an X chromosome, the embryo develops into a girl with an XX genotype. When the sperm carries a Y chromosome, a male embryo consequences, with an XY genotype.
• Parents donate a hard and fast of chromosomes to their offspring, 23 from each for a complete of 46. Each of these chromosomes includes the genetic facts that determine the entirety from the child's eye and hair colour to the baby's intercourse.
• Gender is determined via the intercourse chromosomes. If the Y chromosome is present, the baby could be a boy.
• The genetic records in the Y chromosome consist of the commands to broaden the embryo into a male; especially, the chromosome has a place called the intercourse determining region Y (SRY).
• Until approximately week seven of being pregnant, a male embryo and a woman embryo aren't any different.
• Around this time, genes cause the formation of the testes in a male embryo. The newly formed testes start generating hormones, which includes testosterone, that also make contributions to the bodily traits of a male.

Hence, the correct answer is option (A).

Note: Chromosomal intercourse is decided on the time of fertilization, Gonadal sex refers to the gonads, this is the testis or ovaries, relying on which genes are expressed. A human foetus does not increase its sexual organs outside until seven weeks after fertilization. The foetus seems to be sexually indifferent, searching neither like a male nor a woman.