Which of the following is $NOT$ true for $Drosophila$ $melanogaster$?

Read the following statements carefully $:-$
$(a)$ Linkage is physical association of genes on a chromosome.
$(b)$ In $Drosophila$, genes of body colour and eye colour are tightly linked on $X$-chromosome.
$(c)$ In honey bee a fertilised egg develops as a male $(drone)$.
$(d)$ In grasshopper males have only one $X$-chromosome besides the autosomes.
$(e)$ $Drosophila$ can complete their life cycle in about two months.
Choose the correct option having all correct options.

Identify the wrong statement.

When a plant of $F_1$ generation is crossed with homozygous dominant parents,it is known as

Mother and father both have blood group '$A$'. They have two children,one with blood group '$O$' and the second one with blood group '$A$'. They have:

How do genetic disorders arise? Explain by giving suitable examples.