in order to be a correct sentence, it needs a subject and a verb.
Yes, a declarative sentence makes a statement or expresses a fact, opinion, or idea. It ends with a period.
Fair and acceptable are both definitions for valid
A sentence that makes a statement
A declarative sentence makes a statement and uses a period.
A declarative sentence is a type of sentence that makes a statement or expresses an idea. It usually ends with a period. For example: "The sun is shining."