Grasses Sequester Silica Which Makes Them Difficult to Chew

Question

Grasses sequester silica which makes them difficult to chew. This defense is
A) Mechanical
B) Chemical
C) Associational resistance
D) Mutualism with a defensive agent
E) Semiochemical

Accepted Answer

Grasses sequester silica to make their tissues harder and more abrasive, which physically deters herbivores from eating them. This is a mechanical defense mechanism.