Some mutations occur at the same locus of a chromosome. They produce ..........

$A$ pair of contrasting characters is termed as

Can a child have blood group '$O$' if his parents have blood group '$A$' and '$B$'? Explain.

$A$ man with blood group $A$ marries a woman with blood group $AB$. Which type of offspring would indicate that the man is heterozygous for blood group $A$?

Genes located on homologous chromosomes for the same trait are called.....

$A$ child with a mother of $O$ blood group and a father of $A$ blood group will have which of the following blood groups?