Final answer:
Mary's resemblance to her mother is attributed to her inheritance of her mother's genes, which determine physical traits. Genetics explains the inheritance of these traits and can also indicate hereditary health conditions, like certain cancers.
Step-by-step explanation:
Understanding Genetic Inheritance
The reason for Mary's resemblance to her mother is because she inherited her mother's genes. Our physical characteristics, such as height, eye color, and facial features, are determined by a combination of genetic information from both parents. During sexual reproduction, a child receives 50% of their genes from their mother's egg cell and 50% from their father's sperm cell. Genetics, the science of heredity, explains how traits are passed from one generation to the next. Each child inherits a unique set of genes, which is why siblings can look alike but also have differences, except in the case of identical twins who share the same genetic information.
In the case of diseases like cancer, family history can be important, as certain types of cancer can be linked to specific genetic mutations which may be inherited. In the provided case study, Rebecca's family history of cancer, especially breast and ovarian cancer, might indicate a genetic predisposition, which is why her doctor inquired about her relatives' health history.
It's important to understand that genetics is responsible not only for visible traits but also for unseen genetic conditions that can impact health. Therefore, knowledge of family medical history is crucial in proactive health care management.