Because she wants to travel to Europe, Teresa is saving all of her money. what type so sentence is this

A complex sentence is a sentence that contains one main clause (or independent clause) and at least one subordinate clause (or dependent clause). An independent clause is a sentence that can stand alone and make sense without any other added information. A dependent clause is a sentence that depends on more information in order for it to make sense. Here, we have one independent clause, "Teresa is saving all her money" and one dependent clause, "Because she wants to travel to Europe". So yes, I would say that this is a complex sentence.