arrays

A couple of simple ones here ... the usual references don't appear to give a straightforward answer on these: Can arrays be passed to functions just like a simple variable? Can arrays be passed as values in hidden form fields just like a simple variable? I've been playing around with these and getting inconsistent results. I've been trying things like serialize and urlencode, but still haven't worked out a straightforward 'rule' or policy. Can someone throw some light on this? TIA Michael