Which subdivision of anatomy involves the study of organs that function together?

It is the macroscopic anatomy with a systemic approach.
There are two levels of the human body: macroscopic (gross anatomy) and microscopic level. For each of the two levels, there is a separate subdivision of anatomy.
There are two approaches for gross anatomy:
1. Regional approach-human body is divided into regions like arm, forearm, wrist etc. Structures within that region are studied simultaneously.
2. Systemic approach-the body is divided into organ systems like skeletal system, or nervous system and structures belonging to one system are studied together.

Hahaha good one. you ? & oop