Answer:
many
pollution by dumping chemical that are harmful to the animals
littering by plastic
accidentally introducing invasive species
over fishing
 
it lowers the biodiversity of the aquatic ecosystems living there
Explanation:
 
        
             
        
        
        
The answer would be thermal insulator, hope it works goodluck
        
                    
             
        
        
        
The heart is a hollow cone shaped muscular pump within the thoracic cavity