Question

read the passage.
from geology of mesa verde national park
the park is best known for the cliff dwellings, impressive homes built within the rocks that provided protection from the elements. these dwellings are found in alcoves, formed by chemical and physical weathering over a long time period. alcoves are similar to caves, but are recesses into the cliff face, whereas caves are underground. alcove formation mostly depends on a physical weathering process called ice wedging. water seeps into cracks in the cliff face and freezes when the temperature is low enough. as water freezes, it expands, and cracks the rock. as the ice in the crack melts, rock debris is carried along as it drips down due to gravity.
... the rocks in mesa verde national park are mostly sandstone with a base of shale. sandstone is permeable, allowing water to travel through pores, whereas shale is not (impermeable). as water travels downward through the rock layers, it is blocked by the impermeable shale and is forced to move horizontally. where the horizontal layer of water reaches the cliff face a seep spring is formed. these fresh water springs were used by the ancient puebloans and were carefully protected with an intricate network of tunnels and wooden ladders.
(from geology of mesa verde national park by u.s. geological survey)
which statement best describes how water impacted the area known as mesa verde national park?

1. water revealed the unique cliff formations by carrying away the loose sand.
2. water helped form the landscape by soaking into the rocks and sealing up cracks.
3. water broke apart rocks that were then used as building materials by ancient peoples.
4. water created places for cliff dwellings and a spring for the ancient peoples living there.

Explanation:

The passage discusses how water, through processes like ice - wedging (a physical weathering process where water freezes, expands, and breaks rocks), seeping into cracks, and carrying away loose materials (as in the case of sandstone being permeable and water traveling through it, while shale is impermeable and blocks water downward movement but forces it to move horizontally creating seep springs), impacts the landscape. Option 2 mentions water helping form the landscape by soaking into rocks and sealing up cracks (which aligns with the ice - wedging and water seepage concepts described in the passage about physical weathering). Option 1 is about water revealing unique cliff formations by carrying away loose sand, but the passage focuses more on the physical weathering process (like ice - wedging) rather than just sand removal. Option 3 is about water breaking rocks for building materials, which is not the main focus of how water impacts the area as described (the main focus is on landscape formation through weathering). Option 4 is about water creating places for cliff dwellings and a spring for ancient peoples, but the question is about how water impacted the area in terms of landscape formation (the physical weathering process described in the passage) rather than human - use aspects.

Answer:

1. Water helped form the landscape by soaking into the rocks and sealing up cracks.