The study of body function in a disease state is the study of body function in a disease state is histology. pathophysiology. necrology. microbiology. physiology.

pathophysiology

Explanation:

This area of medicine study the pathology processes, physical or chemical, that take place in a human body. Study the physical, mechanical and biochemical processes. Study the mechanisms of a sickness at the molecular, sub-molecular, cellular, organic and anatomic level.  

i'd say that the moon rock is about 2.2 billion years old.