$X$-chromosome or $X$-body was first observed by.............

Which of the following is produced from an unfertilized egg?

$XO$ type of sex determination can be found in:

The human embryo contains all the genetic instructions necessary to become either male or female. The male embryo contains a master regulatory gene that acts as a biological switch,turning other genes on and off. The absence of this gene results in a female,which remains sexually immature. This master regulatory gene is located on the .....

What type of sex determination is observed in humans? Explain.

If a character is always transmitted directly from a father to all his sons and from their sons to all their sons,then which chromosome carries the gene for the character?