Answer:
A sequential file is accessed one record at a time, from first to last, in order. Each record can be of varying length.
A direct (or random) file is accessed in any order, by record number. Each record must be of identical length.
A sequential file might look like this, with records separated by commas:
bear,skunk,moose,fish,alligator
A direct file with the same data would look (something) like this:
bear_____skunk____moose____fish_____alligator