Two types of activities are essential if team members are to work well together over time. These two activities are:

A) promoting interactions and sentiments.
B) norm and cohesion building activities.
C) effectiveness and efficiency training activities.
D) task and maintenance activities.
E) developing emergent and required behaviours.

Task activities are focused on the actual work that needs to be done, while maintenance activities are focused on keeping the team functioning effectively by addressing the interpersonal relationships and the well-being of team members. These two types of activities ensure both productivity and a positive team environment, which are essential for long-term success.