Which of the following is a mutagen?

Identify the following point mutations in $mRNA$: $UAU\ ACC\ UAU$ to $UAU\ AAC\ CUA$ and $UUG\ CUA\ AUA$ to $UUG\ CUG\ AUA$.

The unmodified allele which represents the original phenotype is the $.........$ allele and the modified allele is generally the $.........$ allele.

The short-legged breed of sheep,known as the Ancon sheep,is an example of which of the following?

In a mutational event,when adenine is replaced by guanine,it is called:

Mutations that involve a single base substitution are induced by .......