In physical geography<span>, a </span>dune<span> is a </span>hill<span> of loose </span>sand<span> built by </span>wind<span> or the flow of water.</span><span> Dunes occur in different shapes and sizes, formed by interaction with the flow of air or water. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind. The valley or trough between dunes is called a </span>slack<span>. A "dune field" is an area covered by extensive sand dunes. Dunes occur, for example, in some </span>deserts<span> and along some coasts.</span>
        
                    
             
        
        
        
Answer:
It isn't safe at all...
Explanation:
Even if remains at constant temperature, while ascending to the surface of the lake Jacques lung pressure will increase if he hold its breath. Thats because the pressure of water weakens and the pre-hold breath in lungs will expand as he rises. This can cause serious lung damage and drowning is possible.
 
        
             
        
        
        
I think the answer is B, that most amino acids are encoded by more than one codon.