The document provides vocabulary words and definitions for lesson 12 of a reading program. It defines prefixes like "re-", "un-", and "non-" and gives examples. It introduces the topic of the ultimate field trip and wading into marine biology. Students are instructed to read a paragraph and complete a Venn diagram comparing and contrasting land snails and sea snails. They are then told to read the story in their textbook and complete exercises in their practice book.