According to the textbook, one way in which researchers try to disentangle the relationship between personality and health is through a carefully controlled study, in which an initially healthy group of participants would be assessed on variables thought to be risk factors and then the group would be tracked for a specific subsequent period

prospective

Explanation:

A prospective study often known as a prospective cohort study is a type of cohort study, or group study, where participants are enrolled into the study before they develop the disease or outcome in question. Prospective studies usually last a few years, with some (like the  case of the  Framingham Heart Study) lasting for decades.

There is a certain criteria the study participants  have to meet certain criteria to be involved in the study. For example, they may have to be of a certain age, profession, or race. Once the participants are set in motion, they are under studied  for a period of time to see who gets the outcome in question (and who doesn’t). Usually, the research is conducted with a goal in mind and participants are periodically checked for progress, using the same data collection methods and questions for each person in the study. Follow ups might include any of the following   Email questionnaires, p hone, internet, or in-person interviews,  physical exams, i maging or laboratory tests.

world bank is the correct answer.