What is the term for the activity of living organisms?

The term that best captures the activity of living organisms is "behavior." In the context of psychology and biology, behavior encompasses all observable actions and reactions of an organism, influenced by internal and external stimuli. It includes a vast range of activities such as eating, mating, communicating, and fleeing from danger, reflecting how organisms interact with their environment. Each living organism's behavior is often shaped by its needs, experiences, and evolutionary adaptations, making it a fundamental concept in the study of life sciences and psychology.

While "actions" might seem similar, it tends to focus more narrowly on individual deeds rather than the comprehensive spectrum of an organism's interactions. "Tasks" implies a specific goal or assignment, which may not accurately reflect the natural activities of living organisms. "Operations" generally refers to processes or functions that may not directly relate to living behavior in a biological sense. Thus, behavior is the most encompassing and appropriate choice for describing the activities of living organisms.