Barnacles and mussels are filter feeders that attach themselves to rocks in the intertidal zone. a scientist observed a dense colony of barnacles covering a rock surface. the mussels were limited to the crevices in the same rock. evaluate the observation given the limiting factors in the zone.

The barnacles are only able to attach them selfs to surfaces in the water. Since the surface is limited, barnacles are attaching themselves to the other barnacles, crowding the rock. The muscles were not able to grow or attach themselves off the surface of the rock. Same thing with the mussels that are growing on the rock. So not only barnacles are crowding the rock, but Mussels as well are crowding the rock.

the sphincter muscles at the end of the digestive tract is the anus.