Question

how do i respond to ?Por que?

Answer 1

Porque.......
(Because.....)

Answer 2

There are 2 ways to respond. You could start with porque(because) then continue with your answer. But that is not the recommended way. The other way is to put the question in the answer. For example:
?por que es la profesora en la cuarta?
You would say: la profesora es en la cuarta porque.....

Answer 3

In our Spanish courses, we are taught that because the question already brings up the prime info that you can put porque and the readers should know what you are talking about. Typically, that makes just porque appropriate as an answer. As long as you have all the required components then you have an appropriate response. (Spanish 2 w/103 average)