Answer:
Physical Geography matters because we use it to define countries.
Step-by-step explanation:
Physical Geography, like rivers or mountains, matter because they can form the borders between countries. Mountains can be used by a country to protect themselves from an invader, like Switzerland, or rivers could be used to protect themselves from an invader too, so you could see them crossing the river and prevent them from doing so, like Croatia, Serbia, or even Russia! Physical Geography also matters for situations like building a canal or something. Before the Panama canal was built, the US government wanted to build it in Nicaragua because there was a bigger lake there. What they didn't know, was that there was a giant active volcano near their proposed location, and also Nicaragua was alot larger than Panama, and thicker. So, after more consideration from the Physical Geography, they changed the build location.
Hope this helps!