nigeria help: How did team work in an oragnization increase the achievement - Help.com

Team Work defined as “a joint action by two or more people, in which each person contributes with different skills and express his or her individual interests and opinions to the unity and efficiency of the group in order to achieve common goals.” Source - Wikipedia (http://en.wikipedia.org/wiki/Teamwork)

The Team work is basically to achieve common objective (Efficiently and/or effectively) what means reaching this objective in less (Risk, resources, Time, quality, etc…)

To better understand it, image a large wall that your objective is to bring it down with normal hammer, it might take you days to achieve your objective, however with the use of another person to help you, you might reduce the amount of days to half, what means less time and cost for you, and if you used another expert he will be able to assist you in moving the broken stones from ground what will enable you to work even better, and achieve your objective in much less time and cost.

In Today economy, corporate should work more effectively and efficiently to strive and survive, therefore they build their business module on Teamwork and not on individuals.

The answerer for Your question, is To Increase efficiency and Effectiveness.

Also i highly suggest reading more about Groups in corporates.