Becoming a high school or secondary school science and math teacher could be a good option for someone who has studied biology, physical science, and math. This would only be true if the person likes the idea of educating young people, however. Additional studies in order to get a teaching certificate would probably be necessary for this career.
It may be possible for someone with a knowledge of science and math to work in certain businesses, such as ones that sell science equipment or deal with environmental problems. Once again, further training may be needed, though some positions may be available without this training.
Science writing or journalism or science illustration are other possibilities for someone with general science knowledge, although getting a full-time job in these areas could be difficult. Writing or artistic skills would be required for these careers.