Questions

To join 'n' tables 'n-1' conditions should be satisfied.

So to join 4 tables 3 conditions should be satisfied.

Answer A is tempting because it is true by definition, but Answer B is correct because it properly answers the question, in that these techniques do not take into account resource pool constraints. Answer C is incorrect because it provides possible early and late start and finish dates, but not the actual schedules. Answer D is incorrect because none of the the three are simulation techniques. 

26 + 26 + 26 = 78

A person or scientist who studies on water is called as Hydrologist. Since the study of water and its properties is known as Hydrology, the persons who deals with this field are known as Hydrologists.

Geographer :

A scientist who studies Earth's natural environment and how human society uses the natural environment.

Herpetologist :

A person who studies reptiles and amphibians.

Archeologist :

Someone who studies people and what they did in the past from the things they left behind.

A binary semaphore is one, which takes only 0 and 1 as values. They are used to implement mutual exclusion and synchronize concurrent processes.