Test cross involves
crossing between two genotypes with dominant trait
crossing between two genotypes with recessive trait
crossing between two $F_1$ hybrids
crossing the $F_1$ hybrid with a double recessive genotype.
Mendel's principle of segregation means that the germ cells always receive
Organisms phenotypically similar but genotypically different are said to be
The genotypic ratio of a monohybrid cross in $F_{2}$-generation is
Test cross is
$A$ : Mendel gave postulates like "principles of segregation and principles of independent assortment" after studying seven pairs of contrasting traits in garden pea.
$R$ : He was lucky in selecting seven characters in pea that were located on seven different chromosomes