Which one of the following is a physical factor that induces mutation?

$A$: Sickle cell anaemia occurs due to a point mutation.
$R$: $mRNA$ produced from the $Hb^S$ gene has $GUG$ instead of $GAG$.

The primary source of allelic variation is

The following characteristics are most suitable for which of the following processes?
$(i)$ Due to alteration of $DNA$ sequences,the genotype is changed.
$(ii)$ Changes occur in the phenotype.
$(iii)$ Variation is created in $DNA$.

Most natural mutations are ..........

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 $2$?