The correct answer is absence of jaws.
Lampreys and hagfish are in the class Agnatha, they are jaw-less fish. The members of the agantha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian period that occurred 500 million years ago. 
        
             
        
        
        
Answer:
Symbiosis
Explanation:
Another category of interactions between organisms has to do with close, usually long-term interaction between different types of organisms. These interactions are called symbiosis
 
        
                    
             
        
        
        
The answer is Clean Water Act