This section of writing is called a paragraph. A paragraph, is a series of related sentences developing a central idea, commonly known as topic. A paragraph, could also be a group of sentences or a single sentence that forms a unit. Paragraphs, shows the reader the divisions and subdivisions of the central idea; and it helps us grasp the main points. Regardless of the kind of information it might have or contain; it is always related to the main topic.
No, I dont think they should be mandatory, but I do believe that masks should be. Students should get vaccinated to protect others, but at the end of the day it should be their own choice.