In what ways can managers at each of three level of management contribute to organizational efficiency and effectiveness?

1- At first-line level, by directing employees and motivating them to accomplish according to plans.2- At middle level, to prepare the required plans according to the vision and strategy.3- At top-level, to create the vision and strategy to meet organization's objectives.

Thanks for the invitation

Well.......i believe that the answer of Mr.: Raafat Sallem

did covered the question very well and i have no more to add

Agreed with the3 descriptions points given by his answer. 

COMMUNICATION

CO ORDINATION

COMPLETNESS