$A$ : In block inheritance of all genes located on the same chromosome may occur in some organisms.
$R$ : Dihybrid test cross will have only two phenotypes.

In a somatic cell,if the arrangement of genes is such that dominant alleles are present on one chromosome and recessive alleles are present on the other chromosome of a homologous pair,what is this arrangement called?

What do genetic maps represent?

Which scientists proposed the coupling and repulsion theory?

Morgan hybridized yellow-bodied,white-eyed females to brown-bodied,red-eyed males and intercrossed their $F_{1}$ progeny. He observed that:
$(a)$ $F_{2}$ ratio deviated significantly from the $9 : 3 : 3 : 1$ ratio.
$(b)$ Both genes did not segregate independently of each other.
$(c)$ Recombinant types are not obtained in $F_{2}$ generation.
$(d)$ Both genes segregate independently of each other.
Select the correct set of statements:

Linkage groups can be separated during . . . . . . in meiosis.