The person who discovered $Y$ chromosomes was

Which of the following animals can be formed without fertilization?

In humans,recessive genes located on the $X$-chromosome are always:

Which of the following symbols is used to represent the sex chromosomes in birds?

Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?

$A$ medical technician, while observing a human blood smear under the microscope, notes the presence of a Barr body close to the nuclear membrane in the $WBC$. This indicates that the person under investigation is: