C. Validity Effect. After being exposed to something repeatedly, the likelihood increases.
I'm assuming the underlined conjunctions are <em>both </em>and <em>and </em>(because you didn't underline any, and those are the only two conjunctions in the sentence).
Those conjunctions are called correlative conjunctions - this means that they are connecting two items which are equally important. So, this woman saw both Billie Holiday and Ella Fitzgerald - and both of those artists are important to the woman.
The subordinate clause is "unprotected animals got swept out" and the main clause is because "when waves rush in". hope u get it right ;)
