Spanish language Q&A Forum

How to decide to use por (for because) versus porque (as in the example above):

Would it be correct to use porque in these examples?  How would one know which to use (por vs porque)?

Ha salido en la televisión por tener quince minutos de fama.
He's been on TV because he was famous for fifteen minutes.

Va a estudiar medicina por seguir la tradición familiar.
She is studying medicine because it's family tradition.

The question given is: De los dos películas esa es la peor.

The multiple choice answers are

Out of those two films that one is very bad /  better / bad / worse.

Since película is à “feminine “ noun; Should the question not be De ESAS dos películas esa es la peor. Or perhaps De LAS  dos películas esa es la peor.

My understanding is that in Spanish, “un billón” represents a different quantity from “a billion”in English, and this should not be directly translated, but is rather the same as “mil millón.” 

Is my info wrong? Can there be regional variation?

I am wondering why in the question "Which of the following expressions are followed by the subjunctive?" the option "Parece que" was marked as incorrect? There is no any information about it in the explanation. However it is followed by the subjunctive, isn't it?

I have seen three words for car: el carro, el automóvil, y el coche. How do I know which to use? Are these regional? I see a lot about Spanish in Spain vs North America.

I had thought that with the noun 'mano' we shouldn't use the possessive pronoun/s? 

Please could you advise me here? 

Gracias

Clara