The answer is psychoacoustics in which it is the study of the psychological associates the physical measurements of acoustics and it is a branch of psychophysics. In addition to perception, audibility threshold is the lowermost sound pressure level that can be reliably noticed at a given frequency and temporal integration the procedure by which a sound at a constant level is alleged as being louder when it is of the greater period.
Sumer was the first civilization in Mesopotamia.
"for"
"and"
"when"
http://www.marshall.k12.il.us/data/webcontent/245/file/realname/files/List-of-Conjunctions.pdf - Try using this, it'll help. It gives a list of conjunctions.
