$A$ back-cross is a cross between ........

Match the following and choose the correct option:

Column-$I$	Column-$II$
$(p)$ Mendel	$(i)$ Chromosomal theory of Inheritance
$(q)$ Morgan	$(ii)$ Recombination map
$(r)$ Alfred Sturtevant	$(iii)$ Linkage
$(s)$ Sutton	$(iv)$ Law of Segregation

Interspecific crosses are rare in nature and intergeneric crosses are almost unknown. Why?

Which of the following statements are correct?
$(a)$ The $X$-linked genes are located on the non-homologous region of $X$-chromosomes.
$(b)$ Females with the recessive gene on one $X$-chromosome are carriers.
$(c)$ The carrier female is also severely affected by the disorder.
$(d)$ $Y$-linked genes are located on the homologous region of $Y$-chromosome.
$(e)$ Human males have homomorphic sex chromosomes.
Choose the correct option.

'Eugenics' pertains to

Identify the correct statement.