What is simpsons season 17 episode 21?

The 21st episode of season 17 of The Simpsons is titled "The Monkey Suit." The episode aired on May 14, 2006, and was directed by Raymond S. Persi and written by J. Stewart Burns.

The episode revolves around the hot-button topic of the teaching of evolution in schools. When a new teacher, Mrs. Cantwell, arrives at Springfield Elementary, she begins to teach the theory of evolution to the students. This sparks controversy, with many parents in the community, including Ned Flanders, pushing for creationism to be taught instead.

Meanwhile, Homer is chosen to take part in a court case to determine whether or not evolution can be taught in school. The case attracts national news attention, and both sides of the argument are represented by high-profile lawyers.

Overall, "The Monkey Suit" is a satirical take on the ongoing debate between those who believe in evolution and those who reject it in favor of creationism. The episode received positive reviews from critics and is often cited as one of the stronger episodes of the 17th season.