Give one word / phrase / term for the following sentences.

1) The art of getting things done through others.
Ans:- Management

2) The second level of Management.
Ans:- Middle level Management.

3) Systematic body of knowledge.
Ans:- Science

4) The level of management related to Managing Director
Ans:- Top level Management

5) Level of management that link top level and lower level management.
Ans:- Middle level management