Final answer:
A small group is typically one where the members know each other and have simultaneous interaction. The textbook's definition of small groups includes criteria such as a small number of people, a common purpose, and a connection among group members. However, selecting a leader is not part of the definition.
Step-by-step explanation:
A small group is typically one where the collection of people is small enough that all members of the group know each other and share simultaneous interaction. The textbook's definition of a small group includes criteria such as having a small number of people, having a common purpose, and having a connection among group members. The only part that is not part of the textbook's definition is that the group selects a leader. So, the correct answer is: the group selects a leader.