How do I derive the parent question from an answer in the /posts call?

Question

So, I'm parsing every post - question or answer - for a concordance that I am building. (If you're interested, you can see where I am at http://seconcordance.cloudapp.net. Don't worry - full attributions are in there, etc...) My program reads through the body of each question and/or answer to locate Bible references, and then stores links to questions on christianity.stackexchange itself. The logical api is thus /posts, since it returns both questions and answers.

On my index page, I'd like to be able to see the tags associated with the question being asked, or, if the link is to an answer, the tags associated with the parent question. Unfortunately, I see no way to derive the tags of the questions from the /posts route.

Question 1: Am I missing something here? Is it possible to derive the tags directly from posts in some fashion?

Playing around with the filters, it doesn't appear that I can, but I am totally open to the possibility that I missed something.

Question 2: How do I derive the parent question from an answer post?

Barring question 1, the next logical approach would seem to be to make a second API call for each question, using the id of the question in the /questions api call, and return those tags. For questions, this may be inefficient, but it would work.

My problem is, how do I then reassociate the answers with the questions to which they were originally attached? I don't see any property of the answer that links me back to the question, so that internally, I can associate in that fashion.

So, how do I derive the parent question from an answer in the /posts call?