You could do this with JavaScript inserted via the Insert HTML Code Fragment
tool, where on mouseover, a new image of your answer is shown. You can
convert a text box into an image by copy and paste special back into
Publisher as an image, or into an image editing app for conversion. Then
Google for "mouseover JavaScript", or perhaps "image mouseover" for some
free script that might work for you.
Also depending on which version of Publisher you are using, you could use
the Alt Tag for the image. In Pub 2000 right click your image, Picture Frame
Properties and fill in your answer under Alt text at the bottom of the
dialogue window. Then when you mouseover the image, the Alt Tag will appear.
In Pub 2003, the alt tag does not appear on mouseover, so you have to use a
workaround. You
will have to import your images into your site using the Insert HTML Code
Fragment tool vs. embed them.
Here is an example of the code snippet you would insert into your Pub doc
for each image:
<IMG SRC="
http://www.yoursite.com/images/yourimage.jpg" ALT="Whatever
you want the alt tag to say" border="0">
For this to work properly, you will create a folder on your site called
'images'. You will optimize and size your images in your image editing
software before you upload them to your 'images' folder. You
will change 'yourimage.jpg' to whatever you name your image (no spaces),
along with the extension. You will change the Alt text to whatever you want
to read on mouseover describing the image...in your case, the answer to your
question. As per the border, if you change 0 to 1, 2 etc, you get a border.
You'll have to play around with the size and placement of your code fragment
boxes.
DavidF