## **Core Concept**
Morbid obesity, also known as clinically severe obesity, is a condition characterized by a significantly elevated body mass index (BMI) that poses serious health risks. BMI is calculated as body mass in kilograms divided by the square of body height in meters (kg/m^2). It is a critical measure used to categorize individuals into various weight categories.

## **Why the Correct Answer is Right**
The correct answer, , is based on the classification of obesity. According to the World Health Organization (WHO) and other health institutions, morbid obesity or class III obesity is defined as a BMI of 40 or greater. This category of obesity is associated with a high risk of complications such as type 2 diabetes, cardiovascular disease, and certain types of cancer.

## **Why Each Wrong Option is Incorrect**
- **Option A:** . This option suggests a BMI of 25 or greater, which actually corresponds to the overweight category, not morbid obesity. A BMI of 25 to 29.9 is considered overweight, and 30 or greater is considered obese, but it does not specify morbid obesity.
- **Option B:** . This option indicates a BMI of 30 or greater, which is the threshold for obesity but does not specifically denote morbid obesity. Obesity is categorized into three classes: class I (30-34.9), class II (35-39.9), and class III (≥40).
- **Option D:** . This option is . While a BMI of 35 to 39.9 is indeed a serious health concern and falls under class II obesity, it does not meet the criteria for morbid or class III obesity.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that BMI categories are crucial for assessing health risks associated with obesity. The categories are as follows: underweight (<18.5), normal weight (18.5-24.9), overweight (25-29.9), obesity class I (30-34.9), obesity class II (35-39.9), and obesity class III or morbid obesity (≥40). Understanding these categories helps in identifying individuals at risk and planning appropriate interventions. ## **Correct Answer:** .