Secondary cell walls are hardened by the addition of _______ to the _______ layers.

Question

Quizplus · Accepted Answer

Lignin is added to the cellulose layers of secondary cell walls to harden them. Pectin is primarily found in the middle lamella, which is the layer between adjacent plant cells, and is not involved in the hardening of secondary cell walls. Therefore, choices A, B, and E can be eliminated. Cellulose is a primary component of both primary and secondary cell walls, but cellulose on its own is not sufficient to harden the secondary cell wall. Therefore, choice C can also be eliminated.

Secondary Cell Walls Are Hardened by the Addition of _______