On the basis of Mendel's work,which of the following laws were formulated?
$I.$ Linkage
$II.$ Segregation
$III.$ Incomplete dominance
$IV.$ Independent assortment
Choose the correct option.

In a cross between genotypes showing recessive epistasis,the $F_2$ phenotypic ratio will be .....

In humans, albinism is controlled by a recessive gene '$a$'. If both parents are known to be carriers $(Aa)$ for albinism, what is the probability of having $1$ normal and $3$ albino children in a family of $4$ (in $/256$)?

Identify the correct and incorrect statements from the following:
$(1)$ Mendel is considered the father of modern genetics.
$(2)$ Down's syndrome is a sex-linked chromosomal disorder.
$(3)$ Sickle cell anemia is an example of point mutation.
$(4)$ Color blindness is a hereditary trait.
$(5)$ Triploid female flies are found in Drosophila.

It is said that harmful alleles are eliminated from a population over a period of time,yet sickle cell anaemia persists in the human population. Why?

Which one of the following symbols and its representation,used in human pedigree analysis,is correct?