Xylem Vessels, Found in Angiosperms, Have a Much Greater Internal

question 74

Multiple Choice

Xylem vessels, found in angiosperms, have a much greater internal diameter than tracheids, the only xylem-conducting cells found in gymnosperms. The tallest living trees, redwoods, are gymnosperms. Which of the following is an advantage of tracheids over vessels for long-distance transport to great heights?

• A) Adhesive forces are proportionally greater in narrower cylinders than in wider cylinders.
• B) The smaller the diameter of the xylem, the more likely cavitation will occur.
• C) Cohesive forces are greater in narrow tubes than in wide tubes of the same height.
• D) Adhesive forces are proportionally greater in narrower cylinders than in wider cylinders, and cohesive forces are greater in narrow tubes than in wide tubes of the same height.
• E) Adhesive forces are proportionally greater in narrower cylinders than in wider cylinders, and the smaller the diameter of the xylem, the more likely cavitation will occur.