Xylem fibres are made up of – (1) Scierenchyma cells with thin walls (2) Scierenchyma cells with thick walls (3) Parenchyma cells with thin walls (4) Scierenchyma cells with no obliteration in central lumen
(2) Scierenchyma cells with thick walls Explanation: Fibre that occurs as element of Xylem is called Xylem fibre. It is also referred to as Xylary fibre and wood fibre. It is made up of Scierenchyma cells with thick walls.