About how many billion years ago did the big bang occur? a. 5 b. 11 c. 14 d. 19 what is a scientific theory? a. a guess b. a final conclusion that will never be altered or improved c. an idea that is supported by and explains a wide variety of facts d. a hypothesis which evidence proves the universe began with the big bang? a. craters on the moon left by universal forces b. leftover energy in the universe from the event c. the force of gravity d. the existence of atoms

Question 1) Answer C, 14 Million
Question 2) Answer C, An idea that is supported by, and and explaisn a wide variety of facts
Question 3) Answer B, Leftover Energy

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.