They are the energy base of the food chain for all aquatic organisms, without them all aquatic organisms would most likely parish.
        
             
        
        
        
Peptide bond joining the amino acid togather
        
             
        
        
        
Answer:
B.sea floor spreading
Explanation:
The creation of new crusts at the middle of the mid- ocean ridges is also sea floor spreading. 
The process of sea floor spreading entails the creation of new crusts at the margin of the oceanic crusts. 
Basaltic materials from the subsurface upwells to the surface. 
They cool and solidifies to form new crusts. The old crust is moved behind and away from the margin. This way, sea floor is formed and it spreads in like manner. 
At this margin sea floor is created and at a convergent margin, it is destroyed.
 
        
             
        
        
        
Answer:
B. retain its urine in it’s blood stream
Explanation:
Sharks are cartilaginous fishes that lives in the ocean. Oceans are always salty, hence organisms need to maintain a salt-water balance between their internal and external environment because of osmosis. Sharks are able to maintain this by ensuring that the amount of solutes in their internal environment is as much as that in their external environment.
Sharks retain a chemical contained in urine called UREA in their bloodstream to counter the osmotic effect of the salt concentration in the waters they live. This helps them maintain a concentration balance with their environment.