There are a number of career options for biology majors. Being a teacher myself, I would suggest teaching as one of the career options. A biology major can also go to medical school and become a doctor. They can also look for research positions. However, these options require further study. In some cases, this means years of extra work, especially if you are planning to do a doctoral degree. Without any further study, biology majors can apply for junior level research positions in a clinical setup or at research companies and universities. Science writing is also an upcoming job, although a number of people do it part-time and not as a full-time occupation. Biology majors find can find employment at universities, hospitals and medical centers, research organizations, zoos, national parks, government agencies, and pharmaceutical companies, among many others.
Hope this helps.