Analysis of the sentence structure:
- The sentence "He sings a song and simultaneously plays the guitar" consists of two independent clauses joined by the coordinating conjunction "and."
- The subject of the first clause is "He," the verb is "sings," and the object is "a song."
- The subject of the second clause is implied to be "He," the verb is "plays," and the object is "the guitar."

Type of sentence:

Compound sentence:
- The sentence is a compound sentence because it contains two independent clauses, each capable of standing alone as a complete sentence.
- The two independent clauses are joined by the coordinating conjunction "and," indicating a relationship between the actions of singing and playing the guitar.

Explanation:
- In a compound sentence, the clauses are equal in importance and are connected by coordinating conjunctions (and, but, or, nor, for, yet, so).
- In this sentence, the actions of singing and playing the guitar are given equal weight and are both considered integral to the overall meaning of the sentence.
- The coordination of these actions suggests a sense of multitasking or simultaneous performance, adding depth and complexity to the sentence structure.