Which of the following research questions would be the most appropriate selection for a student studying space exploration? A. Is space travel the future of human kind?

B. Have we been visited by aliens?

C. What potential resources could be gained from the rise of asteroid mining?

D. Should we stop funding NASA?

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