When interspecific interactions lead to competitive exclusion, the weaker competitor is forced to retreat to a more restricted niche (its realized niche) than it otherwise would inhabit in the absence of the competition (its fundamental niche). This is what happens between Balanus and Chthamalus .

The current thought on the structure of the cell membrane is: a. a static phosphate sandwich of lipids b. a fluid-mosaic of phospholipids and proteins c. a bilayer of proteins with static lipid molecules d. an impermeable bilayer of protein molecules e. a static and permeable phospholipid single layer