The thin layer of water that covers most earths surface is called the hydrosphere.
        
                    
             
        
        
        
A=atomic mass  
Z=atomic number  (nº of protons).
N=neutons.
A=Z+N
Data:
A=39
Z=19
A=Z+N
39=19+N
N=39-19=20.
It therefore has 20 neutrons in its nucleus. 
        
                    
             
        
        
        
Answer:
Explanation:
Pascal's law states that when there is an increase in pressure at any point in a confined fluid, the pressure is equally distributed at every other point in the container.
The formulas that relate to this are given below:
P1 = P2 (since the pressures are equal throughout).
P2 is the pressure transmitted in the hydraulic system
N.B : P= Force/ Area
Therefore we have  
F1/A1 = P2 
F1= the force exerted by the driver = 100N  
P2= 100/A1 N/m² or 100/A1 pa or 100/(101325× A1) atm
 
        
             
        
        
        
Energy Transformation is the process of changing one form of energy to another form...
        
                    
             
        
        
        
Explanation:
Radiation biology is the study of the effects of ionizing radiation on living organisms, when this radiation is absorbed in biologic material, ionization and excitations occur in a pattern that depends on the type of radiation involved, considering how far the primary ionization events are separated in space, radiation can be sparsely ionizing (for example, an x-ray or a gamma-ray) or densely ionizing (for example, a proton or an alpha particles). 
<em>DNA is the most critical biological target because of the limited redundancy of the genetic information it contains, most lesions are reparable, but those produced by densely ionizing radiation are generally less reparable than those produced by sparsely ionizing radiation. Densely ionizing (high LET) radiations, therefore, typically have a higher relative biological effectiveness.</em>
I hope you find this information useful and interesting! Good luck!