Before the body was sent to the crematorium, shilling and Crump filled the casket with animal bones, meat, and a mannequin.
Object of the preposition: genius. The subject of the sentence is called a noun clause. It is a clause because it has its own subject and verb. It is also a dependent clause which cannot stand on its own because of the word that (a relative pronoun) at the beginning of the clause. A noun clause functions as a regular noun in a sentence.
The answer is a sentence fragment because it has no predicate. Again, there is a subject-predicate pair (he sharpened) but that pair is part of a dependent clause. Special case: Imperative. Many languages allow the omission of a subject because the verb conjugation implies only one (or very few) matching pronouns. sentence is a complete thought with a noun and verb. A sentence fragment is just part of a sentence and does not make a complete thought. The above are sentences.