the smiths have four children and all are girs but the fifth child is a boy.why did this change occur?
a)the law of averages finnaly cathcing up.
b)the fathers contribution to a y chromosome
c)the mothers contribution to a y chromosome
d)the timing of fertelity cycles
If a boy was born, it was because he got an X chronosome from mom, and a Y from dad.
so the answr would be c?
Jessica -- as Bobpursley pointed out, boys get the X chromosome from their mothers. C doesn't say that.
Please read your materials over and try again.
The correct answer is b) the father's contribution to a Y chromosome.
Explanation:
In humans, the sex of a child is determined by the combination of chromosomes inherited from the parents. A typical sperm cell from the father carries either an X or Y chromosome, while the egg cell from the mother always carries an X chromosome. When fertilization occurs, if the sperm carrying the Y chromosome fertilizes the egg, the resulting child will be a boy. On the other hand, if the sperm carrying the X chromosome fertilizes the egg, the child will be a girl.
In the scenario given, the Smiths had four girls (presumably due to the fertilization of the egg by sperm carrying the X chromosome). However, upon conceiving their fifth child, the father's contribution included a sperm carrying a Y chromosome, which fertilized the egg, resulting in a boy.
Therefore, the change in the gender of the fifth child occurred due to the father's contribution of the Y chromosome, which determines the male sex.