Topics for a 1-2 minute oral presentation vary greatly, based on the type of presentation which is to be made. Let us suppose, for example, that your assignment is to do a "how to" presentation. In this case, choose something which is very familiar to you. It could be something quite serious, or something humorous, or something educational. You could tell the class how to make chocolate chip cookies. You might decide to put the recipe on the board, or even hand it out in written form, if this is allowed by your teacher for the assignment.
You could explain how to cream the butter and sugar together with a mixer, then show them the mixture, which you have brought with you from home. Go through the additional steps, showing them the mixture in various stages. You could finish by telling them what temperature to use for baking, how long to bake them, how to cool them on a rack, etc. You might end your presentation by letting your peers actually eat a cookie made in this method, which you prepared at home.
If your presentation is to be persuasive, you might explain why it is so important to wash your hands thoroughly after using the restroom. You can easily find all the information you need through "Google," or a similar website. You can finish by telling them that they should mentally sing through the "ABC" song twice while washing their hands. This will assure that they have washed long enough.
Always make your subject be the reflection of something you are already familiar with, rather than having to learn a new subject, yourself. It's also important, in a classroom situation, to speak about something your classmates will also be familiar with, or, at least, find interesting. In fact, you might give an oral presentation on how to choose the subject for an oral presentation!
I've heard excellent oral presentations on "why you should not give table scraps to your dog," "how to do laundry," "how to put your hair in a pony tail," "how to choose and apply makeup," "reasons why chewing gum is a good thing to do," "how to parallel park," etc.
If you want to make a more serious presentation, tell your listeners why voting is important, or how to save money, or why they should take a class on health, or which professions are likely to be in demand over the next 8-10 years, etc.
The most important things to remember are that your subject will not be interesting to your audience if it isn't interesting to YOU; it CAN be serious, but it can also be funny or entertaining; PRACTICE your presentation at least 10 times before standing in front of the class. Time your presentation to be certain you use your time wisely. If possible, give your presentation to family or friends who won't be in the class ahead of time. They can tell you if everything you said was clearly understood, etc.