Final answer:
Intervening opportunities enhance supply/demand interactions between distant complementary areas.
Step-by-step explanation:
Intervening opportunities enhance supply/demand interactions that might develop between distant complementary areas. This means that when there are vacant ecological niches nearby, isolated regions with suitable habitats, or many large trading partners nearby geographically, it increases the level of trade or the chances of interaction between complementary areas. These intervening opportunities provide new possibilities for supply and demand to develop, enhancing the overall interaction between distant areas.