BIOLOGICAL CLASSIFICATION
KINGDOM PLANTAE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
I, II and III
|
|
|
I, II and IV
|
|
|
II, III and IV
|
|
|
I, II, III and IV
|
Detailed explanation-1: -Most gymnosperms lack vessel elements in their xylem, unlike flowering plants which have both vessels and tracheids. The vessel element is typically found in the Angiosperms (flowering plants) and it is absent in the Gymnosperms as these plants do not produce flowers.
Detailed explanation-2: -Similarly, in angiosperms, each sieve tube element is normally associated with one or more nucleated companion cells but in pteridophytes and gymnosperms, phloem is without companion cells.
Detailed explanation-3: -Most of the diameter of mature conifer stems consists of secondary xylem (wood) produced by the vascular cambium, a permanent cylinder of dividing cells that lies just inside the bark.
Detailed explanation-4: -The xylem of gymnosperms is devoid of vessels.