Final answer:
The need for further research to understand the factors contributing to increased longevity among church-attending African Americans is evident, as the observation of longer life spans could be influenced by many aspects of social support, lifestyle, and community involvement rather than a direct causal effect of church attendance.
Step-by-step explanation:
As a skeptical scientist recognizing a study that showed African Americans who attend church regularly live an average of 13 years longer than African Americans who never attend, one would most likely identify b) the need for further research to understand the underlying factors contributing to increased longevity. It's essential to consider various factors such as social support, lifestyle, dietary practices, health care access, and possibly genetics that could influence longevity.
The initial observation does not necessarily imply a direct causal relationship but rather suggests the possibility of a correlation that warrants deeper investigation to determine if the relationship is indeed causal or if other confounding factors are at play.
Ethnicity and religion can intersect in complex ways, affecting social support networks and lifestyle habits, which in turn can influence health outcomes. Moreover, attendance at religious services might be correlated with other aspects of social and community life, which could contribute to longevity. Thus, it is premature to conclude a direct causal link without rigorous research that controls for relevant variables.