By what name is the branch of biology related to the study of heredity and variation known as?

Farmers selected swollen parts of wild cabbage and developed the variety known as ..........

$A$ cross was carried out between a pure-bred tall pea plant and a pure-bred dwarf pea plant,and $F_{1}$ progeny was obtained. Later,the $F_{1}$ progeny was selfed to obtain $F_{2}$ progeny. Answer the following questions:
$(a)$ What is the phenotype of the $F_{1}$ progeny and why?
$(b)$ Give the phenotypic ratio of the $F_{2}$ progeny.
$(c)$ Why is the $F_{2}$ progeny different from the $F_{1}$ progeny?

Two pink coloured flowers on crossing resulted in $1$ red,$2$ pink and $1$ white flower progeny. The nature of the cross will be

Select the statements that describe characteristics of genes:
$(i)$ Genes are specific sequences of bases in a $DNA$ molecule.
$(ii)$ $A$ gene does not code for proteins.
$(iii)$ In individuals of a given species,a specific gene is located on a particular chromosome.
$(iv)$ Each chromosome has only one gene.

Explain the following:
$(a)$ Speciation
$(b)$ Natural Selection