Why Do Text Books in Different Countries Agree?

As we gain more knowledge as a species, we change our text books. Science is very different. Evolution may or may not have happened on the textbook. We ad that could be an issue. But also details, let's say, about the molecular structure of certain things, or the atomic structure,. And you know, when my parents were in high school and college, the knowledge they had is very different that we had. The frightening thing about this is that it can happen. It has happened in history. It is happening now.