the most obvious question

Giganews Newsgroups
Subject: the most obvious question
Posted by:  Lazypierrot (lazypierr…
Date: Fri, 5 Dec 2014

Hi, I would like to know the meaning of "the most obvious question" in the following passage.

The most obvious question to ask about zebras is why they are striped. Unfortunately nobody really knows the answer.

I suppose that "an obvious question" is the one that is so easy to answer that everyone knows the answer.  But here, it seems to be completely the opposite.

I would be glad if you could paraphrase the meaning of "the most obvious question."