When data are ordered from lowest to highest but you don't know by how much any two scores differ, you are likely to be measuring on what measurement scale?

Middle adulthood is

A) marked by feelings of chaos and crisis. B) a contemporary phenomenon, basically nonexistent before the twentieth century. C) hard to define because few variations in attitudes and behaviors exist from early adulthood. D) more about aging mentally than physically.

Pain-controlling chemicals in the body are called ________

a) neural regulators b) histamines c) androgens d) endorphins