Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Each species has a characteristic number of chromosomes. Chromosomes are coiled structures made of DNA and proteins called histones ( Figure below ). Chromosomes are the form of the genetic material of a cell during cell division. See the "Chromosomes" section for additional information. Answer: chromosomes
Output:
Each species has a characteristic number of what coiled structures made of dna and proteins?