Final answer:
The option that is not part of the physical domain is 'Understanding the role of health care providers', as this relates more to the social domain of human development. Option a. is correct.
Step-by-step explanation:
Among the options provided, a. Understanding the role of health care providers is not part of the physical domain of development. Developmental psychologists study human growth and changes across several domains. The physical development domain typically focuses on the changes in our body and brain, the development of our senses, motor skills, and overall health and wellness throughout our lifespan. This includes abilities like reflexes and visual perception, as well as skills such as coordinating complex movements and associating sensory stimuli with learned behaviors.
Pro-social behaviors, although they can manifest through physical actions, are actually part of the social or emotional domains of development. These domains encompass the growth and changes in our interactions, emotions, and social skills.