Suppose that exposure to a chemical mutagen results in a change in the sequence that alters the 5' end of intron 1 (i₁). what might occur?
a. loss of the gene product
b. loss of e₁
c. premature stop to the mrna
d. inclusion of i1 in the mrna
e. exclusion of e2

d. inclusion of I1 in the mRNA

Explanation:

Introns are any nucleotide sequence within the gene that is non-coding and it is usually removed  by RNA splicing.

When an RNA transcript is made, it is considered as pre-mRNA. The pre-RNA  contains both the introns and the exons. For it to mature into mRNA, the introns should be spliced and the exons are joined together to form the mRNA.

A mutation might result to the intron I1 not getting spliced hence it will be included in the mRNA.