Which plant is used as a model system in the study of plant genetics?

Mendelism was rediscovered by:
$I.$ Morgan
$II.$ De Vries
$III.$ Correns
$IV.$ Tschermark
Choose the correct option.

$A$ recessive mutant is one which:

$A$ factor (allele) is dominant if it is expressed in ...............

Match the following (Column-$I$ with Column-$II$):

Column-$I$	Column-$II$
$a$. Allele	$i$. Two alleles of a gene are identical
$b$. Genotype	$ii$. An individual having two different alleles of a gene
$c$. Homozygous	$iii$. Genetic constitution of an organism
$d$. Heterozygous	$iv$. Alternative forms of a gene

Mendel studied seven different traits in pea plants. The number of contrasting traits associated with flowers, pods, and seeds, respectively, were ....