Which term describes the absence of adequate physical activity in one's lifestyle?

The term that describes the absence of adequate physical activity in one's lifestyle is "sedentary lifestyle." A sedentary lifestyle is characterized by prolonged periods of inactivity, such as sitting or lying down for most of the day, with minimal physical movement or exercise. This can lead to various health issues, including obesity, cardiovascular disease, and decreased overall fitness levels.

The other choices reflect positive aspects of physical activity or health management. An "active lifestyle" implies regular engagement in physical activities, while a "fitness routine" indicates a structured plan for exercise. A "health-conscious approach" encompasses a broader awareness and effort towards maintaining good health, including diet and exercise. In contrast, a sedentary lifestyle lacks these elements and is marked by insufficient physical activity.