Question

practice passage 1
data collected by the mars rover curiosity at the gale craters
murray formation are suggestive of hydrological deposition of
sediment in the distant past. to characterize the nature of the
depositional environment, frances rivera - hernández et al.
analyzed the grain size of murray formation sediment, finding
that although there are intervals of coarse grains, most of the
sediment consists of fine grains that show signs of cracking due to
episodic desiccation. rivera - hernández et al. concluded that the
coarse grains are sandstone, which tends to be deposited by
flowing water, whereas the fine grains are mudstone, which is
slowly deposited by settling out of suspension in low - flow water,
leading the researchers to posit that ____
which choice most logically completes the text?
a although the area of the murray formation
experienced a prolonged period of dryness that
prevented a lake from forming, water flowing
from a distant source was present.
b a lake existed at the murray formation for a
prolonged period, though the lake occasionally
experienced drying and there were periods in
which one or more streams were present.
c one or more streams existed at the murray
formation for an extended period until being
replaced by a lake that persisted for only a brief
period before permanently drying.
d a stream - fed lake was present at the murray
formation for an extended period, and
although the streams experienced occasional
drying, the lake did not.

Explanation:

To solve this, we analyze the passage: The coarse grains (sandstone) are deposited by flowing water (intervals), and fine grains (mudstone) (most of sediment) are from low - flow water (settling out, forming mudstone, signs of cracking from desiccation). So a lake (fed by streams, since streams have flowing water for sandstone intervals) was present for long, and streams had occasional drying (but the lake didn't dry as fine grains are most, meaning lake was stable overall). Let's check options:

• Option A: Says a lake didn't form, but fine grains suggest a lake (mudstone from low - flow, lake - like environment), so A is wrong.
• Option B: Says the lake occasionally dried and streams were present. But the fine grains are most, meaning the lake was the main feature, and streams were intervals. B's description of the lake drying is incorrect as fine grains show desiccation (maybe the mud dried, but the lake persisted).
• Option C: Says the lake was brief, but fine grains are most (suggesting long - term lake), so C is wrong.
• Option D: A stream - fed lake (streams for coarse grains, lake for fine grains) was present long. Streams (for coarse grains) had occasional drying, but the lake (from fine grains, low - flow, stable) did not dry. This matches the sediment analysis: coarse (streams, intervals) and fine (lake, most).

Answer:

D. a stream - fed lake was present at the Murray Formation for an extended period, and although the streams experienced occasional drying, the lake did not.