Students voices filled the auditorium The lawyers fees exceeded two million dollars.
The dogs barking kept me up all night.
The soldiers parents worried about their children.

where should i place the apostrophes ?

either online or traditional classroom can work for students. which is better will depend on students and teacher. students may have trouble following a lesson in classroom while they can study at their own pace online. other students may have trouble staying focus on their own in online classes. teachers are more used to classroom teaching but they may also be more worry about their jobs teaching online classes and work harder.

a. energy is conserved on earth, but matter is not.