Question

which of these are evidence of glaciation? select all that apply. *
wide, u - shaped valleys
tropical fossils
bedrock scratches (striations)
large meltwater lakes
desert sand dunes
4 points

Explanation:

• Bedrock scratches (striations): Glaciers carry rocks and debris. As they move, these rocks scrape against the bedrock, creating striations.
• Large meltwater lakes: Glaciers melt, and the meltwater can accumulate to form large lakes.
• Wide, U - shaped valleys: Glaciers erode valleys. The erosive action of glaciers (plucking and abrasion) over time shapes the valleys into a wide, U - shape (as opposed to the V - shape of river - eroded valleys).
• Desert sand dunes are formed by wind action (aeolian processes) and have no relation to glaciation.
• Tropical fossils are related to past or present tropical climates and not glaciation.

Answer:

Large meltwater lakes, Bedrock scratches (striations), Wide, U - shaped valleys.