Given a scientific question, generate a correct answer to it.

[EX Q]: Plants have a touch response known as what?
[EX A]: thigmotropism

[EX Q]: Inside each lymph node is a honeycomb of connective tissue with spaces filled by what?
[EX A]: white blood cells

[EX Q]: What type of light is composed of many rays having random polarization directions?
[EX A]:
unpolarized light