Final answer:
Genetics plays a significant role in determining our susceptibility to disease and response to drugs, but it is not the only factor. Probability and inheritance rules come into play when predicting offspring genotypes and determining the likelihood of a given phenotype.
Step-by-step explanation:
In genetics, the percentage of contribution from genetics can vary depending on the specific trait or disease being studied. While genetics plays a significant role in determining our susceptibility to disease and our response to drugs, it is important to note that it is not the only factor. Environmental factors and lifestyle choices also play a role in our overall health. However, when it comes to predicting offspring genotypes or determining the likelihood of a given phenotype, probability and inheritance rules, based on the random segregation of gametes during meiosis and the union of gametes during fertilization, come into play. These rules of probability govern the inheritance of genetic traits and can help us understand the likelihood of certain genotypes and phenotypes in offspring.