What is the purpose of the global positioning system?

a.

to find exact location using satellite signals and receivers

b.

to take aerial photographs using planes and weather balloons

c.

to study weather patterns using radio waves

d.

to analyze maps with software by combining them with data

The answer is A,because of gps

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.

Lol why dont you actually do the work instead of have people do it for you. jk i do it too lol