rewrite the sentence to correct for the vague pronoun reference if necessary. If there is no vague pronoun reference, then do not rewrite the sentence.

1.Online classes have become more and more popular in the last decade, and this has introduced new dynamics to higher education.

2. Many students who take online classes do not realize that the time commitment for online classes is often more demanding than that for face-to-face classes, which often causes the students to fall behind when they take classes online.

3. Most online classes are asynchronous. That is a problem for students who desire immediate feedback.

4. The rate of retention may be lower for online classes than it is for face-to-face classes, which is probably due to the unexpected demands of the online class.

5. Many institutions have begun to offer hybrid courses, which are courses that feature both online work and face-to-face meetings.

6. Many students prefer hybrid courses to online courses. This is because the students enjoy the face-to-face, synchronous time with the instructor that can complement the online work.

7. Online classes can be challenging for teachers as well, which introduces an interesting dynamic into the issue.

8. For some instructors, communicating with students in writing instead of through the spoken word introduces new problems and challenges in instruction. This can lead to misunderstandings between the instructor and the student.

9. Online classes have begun to incorporate audio and video more into their designs. That has helped make the online class a bit more like a face-to-face class for some students.

10. In some cases, students can choose whether to take an online course, a face-to-face course, or a hybrid course. It is really up to them.