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.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: