Simple, compound, or complex sentence All snakes are reptiles

The sentence above is a simple sentence.

Explanation:

A simple sentence has only one or independent clause and no dependent or subordinate clauses. An independent clause is a group of words that can stand alone as a sentence because it has a subject and a verb and forms a complete thought. The NP subject is "all snakes" and the VP predicate is "are reptiles".

This is a simple sentence