what is the difference between tracheids and vessel elements? which looks larger in cross section?
Vessels are wider than tracheids.
The ends of tracheids are closed whereas the ends of vessels are open.
Tracheids have tapering ends whereas vessels have non-tapering ends.
Water passes from cell to cell in tracheids laterally via the pits. Water passes laterally through pits as well as vertically from the ends in vessels.
Vessels are usually an order of magnitude longer than tracheids.
Vessels lack the low end-wall resistance of tracheids.