Which of the following diseases is primarily caused by environmental factors?

The correct answer is that both heart disease and cancer are primarily caused by environmental factors. This is because both conditions can be significantly influenced by a range of environmental exposures.

Heart disease can be linked to factors such as air pollution, which can exacerbate cardiovascular problems, as well as lifestyle choices that are often shaped by the environment, such as diet and physical activity levels. Environmental stressors like chronic noise and chemical exposures can also contribute to the development of heart disease.

Cancer, similarly, has a strong association with environmental factors including exposure to carcinogens such as certain chemicals, radiation, and pollutants found in the air, water, and food. The risk factors associated with lifestyle and the environment play a critical role in cancer incidence.

In contrast, the flu is primarily caused by a virus and is not directly linked to environmental factors in the same way that heart disease and cancer are. While environmental conditions (such as humidity and temperature) can influence the spread of viral infections, the fundamental cause of the flu is infectious rather than environmental. Thus, the relevance of environmental factors is far less significant in the case of flu, making the other two options more suitable as primarily environmentally influenced diseases.