To make whatever the author is trying to say more important
Diachronic change is the "what" that affects constant change on the English language.
what is the text structure of this text?
problem and solution
Explanation:
the problem would be the highlighted sentence, the solution would be "They're considering using a type of gene-editing tool known as a gene drive"
This is because the start of the passage explains that these birds are going extinct because of a mistake they made before, they don't want to make a mistake again, so they offer a well thought out plan, which is to use a type of gene editing tool known as a gene drive.