Atestable hypothesis could be formed from which question?
are bass more active in the daytime than at night?
when whales jump out of water, are they happy?
are red tulips prettier than tulips of other colors?
why are gerbils more popular as pets than hamsters are?

This is all you, but i can give you some topics that you could try. if it rained when you want to do something outdoors, it 'limits' that human activity. maybe you want to do an experiment that goes throughout the whole year and you have to have above freezing the entire year. this 'limits' your activity. i thought of those just off of the top of my head. something that gets to me that might be getting to you is you are thinking too hard about what to do. think simply, and if it is too simple, then bump it up just a little bit.

The correct answer is kettles.

An oceanic-oceanic convergent boundarycredit to user