Which one of the following pairs is an example of intergenic interaction?

The $F_2$ dihybrid ratio $9 : 3 : 4$ is explained on the basis of

In hexaploid wheat, what are the haploid $(n)$ and basic $(x)$ chromosome numbers?

Which of the following statements are false?
$I.$ $A$ dominant allele determines the phenotype when paired with a recessive allele.
$II.$ $A$ recessive allele is weaker than a dominant allele.
$III.$ $A$ recessive allele does not show its effects when paired with a dominant allele.
$IV.$ $A$ dominant allele is always better for an organism.

Which of the following structures is identical in monozygotic twins?

Which of the following is a correct method for the formation of a new species?