What did scientists use to come up with a theory about how the universe was created? a) observation and opinion b) scientific evidence and observation c) scientific experimentation and opinion d) scientific evidence and experimentation
this is a science question

I believe that the correct answer is indeed B.) Scientific evidence and observation. 

My reason being is because in order to know something you have to have evidence ( old dust & light years ) and you also have to have observation , for me in this case it is watching other stars age and blow up , that's how they said the universe was made , something blew up = the BIG BANG THEORY.

I really hope that this helps you a lot.

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.