Why do xylem cells contain spirals of lignin?

A: To prevent the mixing of water with other substances

B: In order to overcome the pressure of water as it moves through the plant

Correct Answer: B. The walls of the xylem are strengthened with a substance called lignin. It helps it withstand the water pressure.

C: To allow the uptake of minerals from the soil

D: To prevent the shrinkage of the plant cells