The short answer is no.
Since all of your content is just that, content in the body of your post, there is no way for the system to automatically know that THIS content is the trigger and THAT content is the collapsed target for the trigger.
In this case, you would have to manually setup the collapse elements like so:
...However, more and more veterinarians are now prescribing this drug for treating feline stress.</p>
[expand tag="h2" title="Can I Give My Cat Paxil? Answer: By Prescription Only"]Yes, you may give your cat Paxil, as long as it is prescribed by the vet. Do not administer the medication yourself without having your pet checked by the doctor....rest of content you want collapsed[/expand]
Sorry, but I don't see any other way of defining what the trigger and targets are.
Now, since you have to go back and 'touch' every page anyway, what I can recommend you do is the following:
1. use a plugin like Types to set up custom fields for your post / page / custom post type. One field for Question, one field for Answer.
2. now, when you go into each of your old posts, you simply copy/paste the question into the question field and the answer in to the answer field.
There are many benefits to doing this, but if this too is beyond the scope of your current skills... shoot us an email referencing this thread to info [at] twinpictures [dot] de and we will spend a few minutes helping you get started. We just did not want to leave you hanging.