Knowing what you know about the interplay between physical, cognitive, and social/emotional development in infancy, consider the role SES (socioeconomic status) may play. Specifically, think about how two babies, one born into a family of high SES and one born into a family of low SES, might develop differently.
Be sure to focus on the integrative nature of development. For example, if you think the two babies' physiological development might be affected in some way, how could that affect their cognitive/social/emotional development.
You should describe two separate potential effects of SES on development. Walk us through why development might be affected by SES and how.