Task/work groups differ from the other three types of groups most dramatically in that they do not focus on

Task/work groups differ from the other three types of groups most dramatically in that they do not focus on the relationships between people.
Rather than focusing on people, task/work groups focus on the task or work that needs to be done or achieved. They are focused on promoting efficient and effective accomplishment of group tasks 

Focus on the satisfaction, motivation and the general well-being of the team members. instead, the task oriented group, which puts much responsibility on the leaders focuses  on the tasks that need to be performed in order to meet certain goals, or to achieve a certain performance standard.