Student lucinda gonzalez studies the composition of black holes that are located in the milky way. identify the appositive or appositive phrase.

First of all, you need to know what an appositive is.
It is a noun or a noun phrase that is used to modify, or refer to another noun which is usually located next to the appositive. In this case, the appositive phrase is Lucinda Gonzalez, because it modifies the noun student.

Explain yourself a little more