Rises and falls is a category of the ballroom dance technique that refers to rises and falls of the body of a dancer achieved through actions of knees and feet (ankles).
This technique is primarily recognized in International Standard and American Smooth dance categories.
Tango is described the "level" or "flat" dance, and its basic technique specifically eliminates rises/falls in the overall motion, with the exception of certain advanced figures and styles.
This may also be misleading if taken out of context: the center of gravity may be lowered, e.g., by bends and sways.
In addition, a certain amount of body rise and fall may be achieved by hip action, used in Latin dance, but absolutely proscribed in Standard and Smooth.