Context: Traditionally the annelids have been divided into two major groups, the polychaetes and clitellates. In turn the clitellates were divided into oligochaetes, which include earthworms, and hirudinomorphs, whose best-known members are leeches. For many years there was no clear arrangement of the approximately 80 polychaete families into higher-level groups. In 1997 Greg Rouse and Kristian Fauchald attempted a "first heuristic step in terms of bringing polychaete systematics to an acceptable level of rigour", based on anatomical structures, and divided polychaetes into:

Question: What two groups are annelids traditionally divided among?
Answer: polychaetes and clitellates

Question: What subtype of clitellates contains earthworms?
Answer: oligochaetes

Question: What subtype of clitellates contains leeches?
Answer: hirudinomorphs

Question: How many polychaete families are there?
Answer: approximately 80

Question: When did Greg Rouse begin trying to categorize polychaetes?
Answer: 1997

Question: What three groups are annelids traditionally divided among?
Answer: Unanswerable

Question: What subtype of clitellates contains spaceworms?
Answer: Unanswerable

Question: What subtype of clitellates contains lemurs?
Answer: Unanswerable

Question: How many polychaete political parties are there?
Answer: Unanswerable

Question: When did Greg Rouse begin trying to categorize planets?
Answer: Unanswerable