Which of the following is the most effective chemical mutagen that induces mutations?

Which one of the following is a base analogue?

The following diagram shows two chromosomes and the letters represent the genes.
Chromosome $1$:

$P$

$Q$

$R$

$S$

$T$

$U$

$V$

$W$

Chromosome $2$:

$E$

$F$

$G$

$H$

Which of the following would result if a translocation occurred between chromosome $1$ and $2$?

Which of the following is a gene mutation?

What is observed in a frame-shift mutation?

Duplication of one or two bases of $DNA$ produces . . . . . . .