After having one concussion you are more likely to have another — some doctorsestimate you increase your risk up to three times. There are two reasons why your risk increases: carelessness and brain chemistry.
        
             
        
        
        
Very, very rare. Uranium used in power plants is typically only 3% U-235 (the explosive stuff), while bomb-grade uranium is nearly pure U-235. Simply, the concentration of U-235 in reactor-grade uranium is too small to start a chain reaction and detonate like a bomb.
        
             
        
        
        
Answer:
the branch of science concerned with classification, especially of organisms; systematics.
Explanation:
 
        
             
        
        
        
The molecules that brings amino acids to the ribosomes are the tRNA molecules.  
        
                    
             
        
        
        
Animals with a three-chambered heart would include Amphibians.
- Amphibians have three-chambered which comprises of two Atria and one ventricle. Examples of Amphibians include Frog, Toads, Salamanders.
- In Amphibians heart blood from the single ventricle travels to the lungs, skin, and body, where it is oxygenated. Before being pumped out of the heart, deoxygenated and oxygenated blood are mixed in the ventricle.
- This is because the Amphibians have low rate of metabolism and thus requires less oxygen for their metabolism.
- As a result heart's load to deliver oxygenated blood to body is lowered.
Thus, from the above pointers we can conclude that only Amphibians from the option have three-chambered heart. 
Learn more about Amphibians:
brainly.com/question/27961653
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