Use the Following to Answer Questions

Use the following to answer questions :
In Joseph Connell's experiments with barnacles in the intertidal zone,he removed two species from their usual zones (stellate barnacles on the upper levels,rock barnacles on the lower levels) and observed the response of the other species.The results showed that stellate barnacles thrived on both levels in the absence of rock barnacles,whereas the rock barnacles remained only on the lower levels.
-The distribution of rock barnacles is restricted by

A) desiccation.
B) cold temperatures.
C) predation.
D) competition.
E) parasitism.