Imagine you are an astronomer who recently discovered a new planet orbiting a distant star. Which set of characteristics would you use to classify this planet as an inner or terrestrial planet? Check all that apply.
D dense and solid
O very large
O thick atmosphere containing hydrogen and helium
O lacking a solid surface
D located near a star

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