Matching longitudinal vessel cells to transverse stem section

Steps:

• Examine photomicrograph X for vascular tissue in the stem's transverse section, focusing on xylem.
• Identify cell types in X: parenchyma (thin-walled), sclerenchyma (thick-walled fibers), xylem vessels (pitted walls), and phloem.
• Analyze photomicrograph Y for longitudinal view showing elongated cells with perforation plates and secondary wall thickenings, characteristic of vessel elements.
• Locate matching clusters of such cells in X, positioned internally near the pith, labeled C.

Why C is correct:

• Vessel elements are xylem conducting cells defined by their elongated, tube-like structure with end perforations, appearing as aligned, thick-walled units in transverse sections at C.

Why the others are wrong:

• A represents phloem sieve tubes, which lack lignified walls and show companion cells, not matching Y's thickenings.
• B indicates sclerenchyma fibers, short and non-perforated, unlike Y's vessel elongation.
• D shows parenchyma cells, thin-walled and isodiametric, not elongated as in Y.

Final answer: C