In Some Rocky Intertidal Habitats, the Barnacle Chthamalus Can Survive

Multiple Choice

In some rocky intertidal habitats, the barnacle Chthamalus can survive across the same depths as can the barnacle Balanus. However, where the two species occur together, Chthamalus adults are found only in the more stressful upper portions of the habitat where they are more able than Balanus to resist desiccation. This is an example of:

A) a mutualistic symbiosis.
B) intraspecific competition reducing the size of Chthamalus' fundamental niche to a smaller realized niche.
C) mutualism reducing the size of Balanus' realized niche to a smaller fundamental niche.
D) competitive exclusion reducing the size of Chthamalus' fundamental niche to a smaller realized niche.
E) competitive exclusion expanding the size of Balanus' realized niche to a larger fundamental niche.