Which of the following is part of the small intestine?

The ileum is indeed a part of the small intestine, specifically the final segment that connects to the large intestine at the cecum. It plays a crucial role in the digestion and absorption of nutrients. The small intestine itself consists of three main sections: the duodenum, jejunum, and ileum, each serving distinct functions in the digestive process.

In contrast, the colon, pylorus, and cecum are not parts of the small intestine. The colon is part of the large intestine, responsible for water absorption and the formation of waste. The pylorus is a section of the stomach that regulates the passage of partially digested food into the small intestine. The cecum is the beginning of the large intestine, connecting to the ileum at the ileocecal valve but is not associated with the small intestine itself. Thus, recognizing the different roles and locations of these structures helps clarify why the ileum is the correct choice.