Which of the following conditions is true for codominance?

When dominant and recessive alleles express themselves together,it is called

Which of the following conditions represents the codominance of genes?

All of these obey Mendel's laws except:

In shorthorn cattle,genes for red $(R_1)$ and white $(R_2)$ coat colour occur. Crosses between red $(R_1R_1)$ and white $(R_2R_2)$ produced $(R_1R_2)$ roan. This is an example of

If two persons with $AB$ blood group marry and have a sufficiently large number of children,these children could be classified as $A$ blood group : $AB$ blood group : $B$ blood group in $1 : 2 : 1$ ratio. Modern techniques of protein electrophoresis reveal the presence of both $A$ and $B$ type proteins in $AB$ blood group individuals. This is an example of: