In order to tailor a political candidate's message to the constituency in a particular area, her staff investigates the area's general age, race, gender, income, and family composition. what aspect of the external environment is the staff investigating

I believe the answer is: Demographic

In political campagin, demographic refers to the different variety of eligible voters based on various factors. (age, income, ethicities, etc). Politicians need to know this information in order to design their campaign in away that appeal to the largest number of demographic as possible.