Hi Saira,
I don't quite understand what it is that you require-- five questions as possible theses for your research paper?
1) Does the Earth have a moon, or are the Earth and Moon twin planets?
2) When was the Sun born, and when will it likely die?
3) Are there more undiscovered planets in our solar system?
4) Are our nine planets always in the same order of relative distance from the Sun?
5) Your choice.