When it has a subject, verb, punctuation, capitalization, a predicate, and a complete thought. A sentence is a sentence when it is handed down by a judge (or a magistrate).
A sentence is a sentence because it has a subject (noun or noun phrase), a predicate ( verb) and punctuation as well as the other parts of speech like pronouns ( she, it him, her, they, them)...
The succulence of watermelons makes them very popular in summer! Many desert animals rely on the succulence of the Prickly Pear cactus as a source of water. A barrier of cactus could be referred to...