Final answer:
Contractions at 2-minute intervals lasting 90 to 120 seconds are typical of the active phase of labor, signifying the progression of childbirth facilitated by a positive feedback loop involving oxytocin release and cervical dilation.
Step-by-step explanation:
The contractions that occur at 2-minute intervals and last 90 to 120 seconds are indicative of the active phase of labor, which is part of the birth process. During labor, uterine contractions help to stretch and dilate the cervix. Initially, these contractions may be less frequent and shorter in duration, but as labor progresses, they can occur as frequently as every 1.5-2 minutes and last around 60 seconds. This positive feedback loop, which involves cervical stretching and the release of oxytocin, causes contractions to become more powerful and efficient, thus facilitating childbirth.