Final answer:
The subject of this question is 'Subject and predicate definition', and the grade is Middle School.
Step-by-step explanation:
The subject of a sentence is the noun or pronoun that the sentence is about. It can be a person, place, thing, or idea. In this question, the subject is 'Subject and predicate definition', which is asking for the definition of subject and predicate.
The predicate, on the other hand, contains the verb and provides information about the subject. It tells us what the subject is doing or what is happening to the subject. In the sentence 'Subject and predicate definition', the predicate is the verb 'define'.
So, to summarize, the subject of this question is 'Subject and predicate definition', and the grade is Middle School.