Which statement about the geography of africa is the most accurate
a) much of the land in africa is below sea leve
b)the variety of geographic barriers has served to promote cultural diversity
c) africa has an irregular coastline with many natural harbors
d )much of the land in africa is tundra and forest

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.