What are the problems of Mother Earth?

Some problems of Mother earth are global warming, acid rain, air pollution, urban sprawl, waste disposal, ozone layer depletion, water pollution, and climate change.

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.

okay so where are the word that i need to use?