Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms. (a) Perianth and two integuments (b) Embryo development and apical meristem (c) Absence of resin duct and leaf venation (d) Presence of vessel elements and absence of archegonia
Option D In gymnosperm except Order Gnetales (Gnetum) xylem consist of xylem parenchyma and tracheids with bordered pits but lacks vessels. So, Gnetales are the most advanced among gymnosperms. They lack archegonia in female gametophyte thus showing similarity with angiosperm and act as connecting link between the two
