The document defines prefixes related to "ad-": 1) "ad-" means "to, toward" and is a prefix found in words like advance, adhere, admission, adapt, adjourn, adjacent, adhesive, and address. 2) It provides definitions and parts of speech for the words adapt, adhere, adhesive, adjacent, admission, advance, address, and adjourn. 3) It gives examples of how humans adapt to their environment through changes in living based on environmental situations like climate or pollution levels.