2 Polnis
A fundamental characteristic of scientific knowledge is that:
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A. direct observation is the only way to confirm a theory.
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B. all scientists agree about how nature works.
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c. scientific explanations are rarely proven to be wrong.
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D. some ideas change as new evidence is found.

Crinoids, also known as sea lilies, appear to be sea plants but are not plants at all. crinoids are an echinoderm species which uses anchoring structures called holdfasts to attach themselves to the sea floor. crinoids were most abundant in pennsylvania during the mississippian period, which ranged from 375 to 320 million years ago. fossils of the crinoids shows that during most of this time pennsylvania was that provided favorable conditions for crinoid growth. a) glacial terrain b) a dry and sandy plain c) mostly mountain ranges d) covered by warm, shallow seas