Tornadoes are common in areas of flat plains because
1. flat plains receive the most heat
2. flat plains receive the most moisture
3. winds are able to flow without obstruction
4. thunderstorms are common in flat plain regions

winds are able to flow with no obstruction

Explanation:

glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as plucking. erosion and transportation of individual pieces of bedrock, especially large "joint block occur as a result of this glacial erosion. plucking is type of erosion in which rocks become frozen into the bottom and sides of the glacier.as the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.

c. is the correct answer