Simple trick to find a subject/verb is to remove words from the sentence until it doesn't make sense anymore:
There are (many freshwater and saltwater) areas (in the everglades).
evergland
freshwater and saltwater
areas
The simple subject is "flowers".
Park
A simple subject is a thing. If it were talking about a Baseball or a sentence the baseball is the simple subject.
The simple subject is "You" and the simple predicate is "waited."
a simple predicate is a verb and simple subject is a noun
The simple subject is "class," and the simple predicate is "have."
SImple Subject: you
Simple: a true solution of a salt in water or another solvent.
Subject: Few people Predicate: had them
The simple subject in this sentence is "fire."