On the basis of Mendel's work which of the following laws were formulated?
$I.$ Linkage
$II.$ Segregation
$III.$ Incomplete dominance
$IV.$ Independent assortment
Choose the correct option
$I, III$ and $IV$
$II$ and $IV$
$II, III$ and $IV$
$I, II$ and $III$
The word 'crossing over' is given by
Select the incorrect statement(s) from the options given below with respect to dihybrid cross.
$I.$ Tightly linked genes on the same chromosome show higher recombinations.
$II.$ Genes far apart on the same chromosome show very few recombinations.
$III.$ Genes loosely linked on the same chromosome show similar recombinations.
Crossing over causes
$A$ : Morgan's cross III was conducted in Drosophila to locate genes on chromosome for white eye colour.
$R$ : The cross was done between red eyed hybrid female and white eyed male.
Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their $F_{1}$ progeny. He observed that
$(a)$ $F_{2}$ ratio was deviated very 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 :