Ten things the Blue people from Avatar 2 could have done to protect themselves from the human invasion

1. Prepared for the human invasion
   
   
2. Invested in powerful telescopes, land-based and orbital ones
   
   
3. Invested more in researching their own biome, and extraterrestrial physics
   
   
4. Launched space ships to threaten the human situation back on earth, as a defensive move
   
   
5. Got some semblance of planetary defense going so they wouldn't be caught pants-down
   
   
6. Elected a visionary war-time leader with great courage who would say things like 'i need bullets, not a ride out of here'
   
   
7. Reverse-engineered human biology and equipment and figure out ways to undermine them for a future threat
   
   
8. Gone at least mildly urban to get economies of scale to be resource-efficient as well as protecting the ecosystem and themselves
   
   
9. Tried united the tribes and people across the planet  / moon for shared defense
   
   
10. Create governments that are larger than small tribal confederacies for better governance and organization