Making Up Answers

I've always thought that people who say that you should never make up answers for a kid, but should offer to look the answer up online later, don't have very talkative children. (And please, no one get offended, of course I'm joking.)

But seriously, if I tried to look up every single answer to every single question that E asks, and then distilled the answer down into something that he could understand, I would never have time to do anything else in life! The kid seriously has a motormouth and a half. Not to mention, some of these things I couldn't find on Wikipedia: "Mom, do horses go to heaven?" My best policy is always to describe a little bit of what I know, ask him what he thinks the answer is, and then, if he still wants more info, just admit I have no idea. Unfortunately, this doesn't always work, and I am forced into the time-honored practice of just making something up. This, too, however, often falls short of expectation. For instance, this recent conversation between my son and me after reading the book "Cars":

E: "Mom, how do cars work?"
Me: [panic, panic, I don't really know, have I ever known?, how could I describe something like this?, should I call my dad and ask?, wait, it's after nine already, is he just stalling?, fine, I'll just tell him something...]
Me: "You put gas in them, and they go."
Pause while answer is pondered
E: "That is NOT what I meant."

Kids are too smart for their parents sometimes. Ok, most of the time, in my case. However, there are still questions that I know the answer to. Like this one:

"If you're going to be a doctor, who's going to be my mommy?"