Why are males considered heterogametic?

$A$ pea plant with blue colour flower denoted by $BB$ is cross-bred with a pea plant with white flower denoted by $ww$.
$(a)$ What is the expected colour of the flowers in their $F_{1}$ progeny?
$(b)$ What will be the percentage of plants bearing white flower in $F_{2}$ generation,when the flowers of $F_{1}$ plants were selfed?
$(c)$ State the expected ratio of the genotypes $BB$ and $Bw$ in the $F_{2}$ progeny.

"It is a matter of chance whether a couple will give birth to a male child or a female child." Justify this statement with the help of a flow chart showing the fusion of sex chromosomes.

By what is the expression of tallness in the pea plant exhibited?

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.

The two versions of a trait (character) which are brought in by the male and female gametes are situated on