barry is applying the principles of relative dating to a building that has been constructed. analyzing a section of the building, barry

says that the lowest part of the section must have been constructed

the parts above it were constructed. he

bases this conclusion on the principle of

. also, looking at a crack forming in the building wall, he says

that the crack must be

the wall. barry used the principle of

to arrive at this

conclusion.

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2010

11

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.