Final answer:
Marissa is most likely experiencing type 2 diabetes, which is often managed with medication that increases insulin release and reduces resistance, a healthier lifestyle, and exercise.
Step-by-step explanation:
Given Marissa's described condition, using antidiabetic drugs that increase insulin release and reduce insulin resistance, she likely has type 2 diabetes. This form of diabetes is often associated with lifestyle factors such as a sedentary lifestyle, and it can also have genetic contributors. In type 2 diabetes, the body's cells become insensitive to insulin or there's an impaired insulin secretion, not necessarily due to autoimmune disease or complete destruction of pancreas cells as seen in type 1 diabetes. Therefore, a potential cause of Marissa's diabetes could be her sedentary lifestyle, and a treatment regimen could include a plan of daily exercise to increase insulin sensitivity, alongside her medication.