Describe the possible cause of a given phenomenon.
Increase in diabetes among teenagers.
The increase in diabetes among teenagers can be attributed to several factors. One of the main causes is the rising prevalence of obesity among young people. Consuming unhealthy, high-calorie diets and engaging in a sedentary lifestyle with little physical activity can lead to weight gain and an increased risk for developing type 2 diabetes. 

Another factor that may contribute to the increase in diabetes among teenagers is the influence of family history and genetics. Children who have a parent, sibling, or other close relative with diabetes are more likely to develop the condition themselves.

Exposure to stress and poor sleep habits can also increase the risk of developing diabetes. Teenagers who experience stress or have poor sleep quality can have elevated levels of cortisol and insulin resistance, which can contribute to the development of type 2 diabetes.

Additionally, teenagers from certain ethnic groups, such as African American, Hispanic/Latino, Native American, and Asian/Pacific Islander, have a higher risk of developing diabetes due to a combination of genetic and environmental factors.

In summary, the increase in diabetes among teenagers is likely to be caused by a combination of genetic and lifestyle factors, including obesity, poor diet, lack of physical activity, stress, poor sleep, family history, and ethnicity.