This would be the Mountain range: the Himalayas.
Himalayas are hard to cross, both because there is no direct line, and one has to go around and because they are a very cold region. Because of this, they hindered contact between India and China.
The correct answer is child-free. Child-free is being
defined or pertained to adults who are likely to live their own life and grow
without having to bear with children or even to live one with a child of their
own or a child.
They can provide the country with money and supplies like the US did in the early parts of world war I and World War II.
