Answer:
In the scopes trial, Thomas Scopes was tried in court because he tried to teach the theory of evolution in Tennessee. The state was highly religious at that time, so they did not want anyone to teach theory of creation that contradicted the Bible.
On the surface, this might be seen as a case that debated evolution and creationism. But, it actually much more than that. it actually will determine whether the State has the ability to suppress knowledge/ideas in order to promote a certain Agenda.
This case became a national debate and eventually the court prohibited the states to force the teaching of a certain religion in public schools.