The efficiency of any machine is given by:
efficiency = output obtained / input given
Substituting the values,
Efficiency = 105 / 150
Efficiency = 0.7
Converting this to a percentage, the efficiency of the hammer is 70%.
This is a fairly high efficiency, and this is due to the fact that the hammer is a simpler machine. The more complex a machine is, the greater are the losses in it due to friction, meaning there is a lower efficiency.
I believe the answer is The Dolphins.
In their Cooperative hunting, The dolphins requires five of its members to form of barrier while one or two of them are herding (Driving) their preys toward the barriers. And each dolphins will always play the same role in their group just like what we see in a football team.