Question

what are trachieds in xylem ? where are they found?

Answer 1

To increase surface area of exchange of gases

Answer 2

The most distinctive xylem cells are the long tracheary elements that transport water. Tracheids and vessel elements are distinguished by their shape; vessel elements are shorter, and are connected together into long tubes that are called vessels. Xylem also contains two other cell types: parenchyma and fibers.