Which risk factor for heart disease cannot be changed by lifestyle modifications?

The selected answer identifies genetics as a risk factor for heart disease that cannot be changed by lifestyle modifications. Genetics refers to the hereditary factors passed down through families that influence an individual's risk of developing various health conditions, including heart disease. These factors can include a family history of heart disease, specific genetic mutations, and how an individual’s body processes fats, sugars, and other nutrients.

On the other hand, the other risk factors mentioned—obesity, high blood pressure, and physical activity—are all influenced by lifestyle choices. For example, obesity can be managed through dietary changes and increased physical activity; high blood pressure can often be controlled through weight management, diet, and exercise; and physical activity levels can be increased through lifestyle adjustments. Therefore, while genetics plays a crucial role in determining one’s predisposition to heart disease, it is not a modifiable risk factor, making it the correct choice in this context.