Answer: Gymnosperm xylem lacks vessels (mostly tracheids); angiosperm xylem has both vessels and tracheids.
- A Gymnosperms are sometimes mistakenly thought to largely lack any xylem tissue for water conduction altogether
- B Gymnosperm xylem lacks vessels (mostly tracheids); angiosperm xylem has both vessels and tracheids
- C Angiosperm xylem is sometimes mistakenly thought to be composed mainly of tracheids with few vessel elements present
- D Gymnosperm and angiosperm xylem are sometimes thought to be structurally indistinguishable from one another overall
Correct answer: B. Gymnosperm xylem lacks vessels (mostly tracheids); angiosperm xylem has both vessels and tracheids
Explanation: Gymnosperms (except Gnetum) have xylem composed mainly of tracheids (no vessels). Angiosperms evolved true vessels, which are wider and more efficient for water conduction. This is one reason angiosperms are more diverse and widespread.
Plants evolved from water-dependent algae through increasingly land-adapted groups, gaining vascular tissue (Pteridophyta), then seeds (Gymnosperms), and finally fruit-enclosed seeds (Angiosperms) - each step reducing dependence on water for reproduction.
Concept context
Classification of plants from algae to angiosperms. Understanding plant diversity is essential for NEET.