How do you rewrite this sentence without vague pronoun reference 1 Online classes have become more and more popular in the last decade and this has introduced new dynamics to higher education?

Try these:

The popularity of online classes over the last decade introduced new dynamics to higher education.

Increased popularity for online classes over the last decade introduced new dynamics to higher education.

Over the last decade, increased popularity for online classes introduced new dynamics to higher education.

New dynamics in higher education resulted from increased popularity of online classes over the last decade.