In sickle cell anaemia$-$

Select the group of $CORRECT$ statements.
$I$. If phenotype of offsprings shows only the dominant trait then the parent plants are heterozygous.
$II$. $A$ true breeding line shows stable trait inheritance and expression for several generations.
$III$. In mendelian experiment material,contrasting characters can be easily recognized.
$IV$. When a single gene controls two (or more) different traits,it is called polygene.
$V$. When interactions occurs between the alleles of different genes present on the same or different chromosome it is called intragenic interaction.

If a daughter is affected by hemophilia,which of the following possibilities applies to her parents?

$A$ hereditary disease,which is never passed on from father to son,is:

In an organism,pink spot is a sex-linked recessive trait and black hair is dominant to white. If a pink spotted black heterozygous female is mated to a white male which is not spotted,the phenotypic ratio of the offspring would be

Pick out the correct statements.
$I.$ Haemophilia is a sex-linked recessive disease
$II.$ Down's syndrome is due to aneuploidy
$III.$ Phenylketonuria is an autosomal dominant gene disorder
$IV.$ Phenylketonuria is an autosomal recessive gene disorder
$V.$ Sickle cell anaemia is an $X$-linked recessive gene disorder