Final answer:
The preventative methods for breast cancer among the given choices are tamoxifen and regular exercise, as they help reduce the risk of developing breast cancer. Tamoxifen blocks estrogen receptors in tumor cells, while regular exercise may lower the risk by improving immune function.
Step-by-step explanation:
The preventative methods for breast cancer include several strategies, but among the choices provided in the question, the correct answers are tamoxifen and regular exercise. Tamoxifen is a medication known to reduce the risk of developing breast cancer in individuals who have a high risk for this disease. It works by preventing the estrogen from binding to estrogen receptors on cells, which is particularly beneficial for patients with a lot of estrogen receptors expressed in their tumor. On the other hand, regular exercise has been shown to help decrease the risk of breast cancer, possibly by improving immune function and reducing high estrogen levels that can promote cancer growth. Some studies have found that physical activity can lower the risk of breast cancer by about 10 to 20 percent. Hormone replacement therapy (HRT), while it may offer relief from menopausal symptoms, has been linked to an increased risk of breast cancer in some studies, making it a controversial and often avoided preventive method.