What is the likely cause of the blockage in the following scenario? A plumber, cleaning out recently blocked lines, indicates that there are roots blocking the sewer system. There are no trees immediately over the sewer line and have not been for years, there is only a small group of trees on the side of the property, several yards from the line.
A. taproots
B. aerial roots
C. lateral roots
D. primary roots

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