Define/Explain: Abscission.

(N/A) Abscission is the natural process of shedding or separation of plant parts such as leaves,flowers,fruits,or branches from the main plant body.
This process occurs at a specific region known as the abscission layer or abscission zone.
It is primarily regulated by the balance between plant hormones,specifically the increase in $ABA$ (Abscisic Acid) and ethylene,and the decrease in auxins.