For a long time, the fact that immigrants from eastern europe, asia, and latin america tended to be shorter than native-born americans was taken as evidence that there were inherent racial differences between these populations. however, the immigrants had children who grew up to be as tall as anyone else. geneticists now tell us that, although there can be considerable variation in height within a group due to genetics, height differences between groups are largely caused by diet. what does this demonstrate?

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