Which cross-section commonly forms where a river cuts down into upland ground?

• A broad U-shaped trough
• A narrow V-shaped valley
• A level plain without sides

Which cross-section is commonly associated with a valley widened by glacial erosion?

• A narrow V-shaped valley
• A broad U-shaped trough
• A level plain without sides

What is a moraine?

• An accumulation of debris left by a glacier
• A channel of water cut through solid rock
• A hollow enlarged by waves along a coastline

A glacier eroded bedrock hollows. After it disappears, why can lakes remain in those hollows?

• The hollows collect rain, meltwater or stream water
• All lake water comes from ice still buried beneath the bedrock
• Rain dissolves the bedrock to create the original hollows

Why can a glacier widen a river's V-shaped valley into a U-shaped trough?

• Ice freezes the rock and stops erosion of the valley
• Ice and carried rocks erode the floor and sides
• Ice leaves the sides untouched and cuts one channel

Scratched bedrock and transported boulders can be evidence that a glacier once moved across an area.

A boulder in glacial deposits matches bedrock far up the former ice-flow route, but not local bedrock. Which explanation fits?

• The boulder formed from local bedrock despite its different rock type
• The different rock type shows that the boulder could not have moved
• The glacier carried the boulder from another place

A river occupies a broad U-shaped valley with scratched bedrock and moraines. A friend says the present river alone made every feature. What challenges that claim?

• Any river in a valley rules out a glacier's past work
• Several observed features support past glacial erosion
• The present river proves the ridges are all river deposits