Answer:
Keeping lakes and rivers free of pollution.
Explanation:
 
        
                    
             
        
        
        
Answer:
A. technology can be used to overcome physical barriers and boundaries
Explanation:
The ability to dam water and use of improved transportation are clear proofs of how we can overcome physical barriers and boundaries. 
- Dam water is an engineering revolution by which water can be made available all year round. 
 - Also, damage to the ecosystem caused by excess water is circumvented. 
 - Roads that are pliable are of huge important in breaching geographical imitations. A good transport system can make use of this connectivity. 
 - Air transportation has improved the ease of travel and reduced travel time greatly. 
 - Both dams and good transportation are clear engineering solutions to overcome limitations of nature.