Answer and explanation:
While writing sentences in Spanish, the subject and the verb must match in person and number, just like in English. Person means discriminating if the subject is in first (Yo), second (Tú) of third person (Él, Ella, Eso) and number implies checking if they are in singular or plural to conjugate the verb accordingly.
Thus, in the examples:
1) Yo canto música romántica.
2) Mi papá toca la guitarra.
3) Vosotros hablan español.
4) Mis amigos trabajan en Argentina.
5) Tú necesitas estudiar la lección.