Final answer:
There are no viable alternative theories to evolution in biology. Teaching non-scientific theories in public schools is illegal and goes against the Constitution. The exclusion of alternative theories is due to their lack of scientific evidence and usefulness.
Step-by-step explanation:
The student is asking about alternative scientific theories that are not taught in public schools and the reasons behind their exclusion. In the field of biology, there are no viable alternative scientific theories to evolution. Some critics of evolution may argue for the inclusion of alternative theories, but these theories lack scientific evidence and usefulness. Additionally, teaching religious-based theories, such as special creation or intelligent design, as science in public schools goes against the establishment clause of the First Amendment and is therefore illegal. The primary reasons for not teaching these non-scientific theories are their lack of scientific validity, inability to foster research programs, and violation of the U.S. Constitution.