3 public questions tagged with this topic.
Xylem vessels are dead at maturity and function in conducting water and minerals from roots to other plant parts.
Ref: NCERT Class 11 Biology Chapter 6: Anatomy of Flowering Plants Secondary Growth - Dicot Stem Root and Wood
Hydraulic anatomy surveys across vascular plants show gymnosperm lineages except Gnetales lack true xylem vessels defined by perforated end walls stacking into continuous low-resistance conduits. Tracheid-only conduction limits conduit diameter, constraining leaf lamina size and photosynthetic capacity and transpiration rates, correlating with needle adaptation. Angiosperms overwhelmingly possess vessels enabling efficient transport supporting broad leaves, high vein densities and rapid growth, though primitive Amborella secondarily vesselless. Dicots and monocots both generally vessel-bearing. Therefore textbook statement vessels absent in gymnosperms remains classical diagnostic differential despite Gnetophyte exception representing convergent acquisition via independent evolution.
Ref: Campbell Biology, 12th ed., Chapter 35: Gymnosperm vessel absence exception Gnetales vessels convergent
The right choice is C: Shorter and wider than tracheids. In PSS- Sec-F-Transport, that matches how the process or concept actually works — the other choices mix up related ideas or use the wrong mechanism. Skip these: A) Narrower than tracheids; B) Absent in angiosperms; D) Present only in gymnosperms. A quick check: if an option needs energy, pumps, or the opposite direction of movement, ask whether that really applies.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.
