Which of the following describes a study that is “longitudinal”? A study that follows people for an extended period of time to see if they develop a disease or condition. A study that looks at people in one location, to reduce any bias introduced by varying locations. A study that follows people taking a drug or placebo for 6 weeks to see if they develop a disease or condition. A study that follows people taking medication in different locations, to see if their location impacts the medication’s effectiveness.