What is rapid change in mood? ? ? (i already know it but just asking)

Mood swings refer to rapid changes in mood. The term may refer to minor daily mood changes or to significant mood changes as seen with mood disorders such as major depression or bipolar depression. Mood swings can also occur in women who suffer from premenstrual syndrome or premenstrual dysphoric disorder.

Explanation:

the plates spread at mid-ocean ridges (they are divergent plate boundaries) which allows magma to rise through the weakness between the plates. the magma then emerges as lava from the boundary and cools, creating a new crust.