Final answer:
Genes for diseases like obesity and heart disease are common due to genetic predisposition and environmental factors. Factors like changes in diet and lifestyle have contributed to the rising rates of obesity. Making healthy lifestyle choices can help prevent the onset of heart disease.
Step-by-step explanation:
Genes for diseases like obesity and heart disease are still common in most populations due to a combination of genetic and environmental factors. In the case of obesity, there are dozens of genes that control appetite and metabolism, and when these genes are present, it increases the likelihood of developing obesity when sufficient food energy is present. Additionally, changes in diet and lifestyle, such as increased calorie intake and decreased physical activity, have contributed to the rising rates of obesity.
Similarly, heart disease is influenced by both genetic and lifestyle choices. While you cannot change your genetic background, making healthy lifestyle choices can help slow or prevent the onset of heart disease.
Overall, genetic diseases like obesity and heart disease persist in populations due to a combination of genetic predisposition and environmental factors such as diet and lifestyle.