What does it mean to be proactive about your hereditary health risks?

Proactive refers to taking control of a situation. Heredity refers to passing on the traits from one generation to another. If there is a health risk in the family which is inherited by the next generation, being proactive is very much necessary. For example, if diabetes runs in the family and grandparents, parents are diabetic, it is better to be proactive against it. The possible health risk should be addressed by taking measures like controlling the carbohydrate intake, having a healthy lifestyle with good physical activity. Being proactive therefore, refers to addressing the heredity problem by taking steps to avoid it than to suffer from it.

D. the best explanation for a set of data and observations
Because a theory is something that cannot become a law (full on solution) but is supported by evidence and different tests from over time. A theory is still in the process of being able to gain more information and being able to be proved wrong by various experiments. I hope I helped! :)