Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Cellulose is composed of very long strands of glucose monomers that are hydrogen bonded to one another. Cellulose is largely indigestible and comprises the cell walls of plants. Answer: cellulose
Output:
What is composed of very long strands of glucose monomers, is largely indigestible and comprises the cell walls of plants?