No, not really. Could be a list of elm tree species, or something even more specific (most famous elm trees, species vulnerable to some disease, etc) that's immediately obvious if you're plugged in to the arborist community instead of the hacker community.
A valid but very unlikely interpretation, which is the point. Every query is ambiguous, but if certain interpretations are much more likely than others, the search engine should respond accordingly.
Someone interested in a list of elm species is much more likely to search for "elm species."
It is very unlikely to be the case. Much more likely is that Bing either doesn't have enough search data to properly answer that query or does not have a ranking model that can answer that query correctly.
