Acline: is continuous variation that follows a continuum. is variation that falls into discrete categories. describes the pattern of occurrence of trisomy 18. was used to describe human variation as early as the renaissance

Cline comes from the word ecoline. The term describes a series of connected populations in a species and the the gradual change in certain characteristics 
exhibited by their members.
From the given options, the one that gives definition of cline is: Cline is is continuous variation that follows a continuum. 

Monophony monophony means music with a single "part" and a "part" typically means a single vocal melody, but it could mean a single melody on an instrument of one kind or another.( just a short note ) : )hope it