Answer to Question 1
Answer: Groups may be characterized by the extent to which they exhibit interdependence, group identity, and group structure. Groups become more grouplike as they possess more of each of the three properties.
Answer to Question 2
Answer: Diversity is most valuable when only one member of a group is required to obtain the correct answer. Heterogeneous groups are better at tasks requiring new solutions, flexibility, and quick adjustments to changing conditions. Diversity can hurt performance on tasks that require each of the members to perform his/her role well. In addition, heterogeneous groups tend to have greater turnover and less frequent and less formal communication.