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

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.

Select the wrong pair from the following:

What is true for the expression of recessive characters?

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

When two genetic loci produce identical phenotypes in both $cis$ and $trans$ configurations,they are considered to be: