Triad of factors determining the severity of malocclusion include:
The effects of any habit depends upon three factors:

Intensity - it is the vigor with which the habit is performed.
Duration - it is the amount of time spent on the habit.
Frequency - it is the number of times the habit is activated in a day.

Above-mentioned triad has direct cause-effect relationship with the habit.
Duration, Intensity and Frequency
Activity, Duration and Frequency
Frequency, Activity and Intensity
None of the above