monophasic

adjective

mono·​pha·​sic -ˈfā-zik 

1

: having a single phase

specifically : relating to or being a record of a nerve impulse that is negative or positive but not both

a monophasic action potential

compare diphasic sense b, polyphasic sense 1

2

: having a single period of activity followed by a period of rest in each 24-hour period

humans are naturally monophasic beings