How are plains formed

1) Plains are formed when everything in the land weathered or eroded away,leaving the land flat.
and
2) Another way is when volcano erupt ,and burn everything in its way,all that is left are the plains,This makes bare land or barren plains.
The most common are from dried up lakes or a glacier moving past an area.

I say The answer is vlocano erupts

[hope this helps]

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.