The answers are: your access to research material, your interest in the topic, and your teacher’s guidelines for the paper.
When conducting research one should always be careful to choose a topic that is feasible, that is to say, that you have access to the research material needed. That could be bibliography, field studies, or even lab equipment.
Also, to make the research more palatable and even enjoyable, it is also recommended that the topic chosen is one that arouses interest in you so that carrying the research will be edifying and constructive for your and for science.
Finally, one should always abide by the guidelines stipulated by your teacher in order to meet the standards and expectations of the exercise.