The answer is X Ray 
Hope it helps
        
             
        
        
        
Answer:
im not smart but here
Explanation:
The strength of the gravitational force between two objects depends on two factors, mass and distance. the force of gravity the masses exert on each other. If one of the masses is doubled, the force of gravity between the objects is doubled. increases, the force of gravity decreases.
 
        
             
        
        
        
Answer:
(b) IE₂ of Ga >  IE₂ of Ge 
Explanation:
Electronic configuration of Ga is [Ar] 3d¹⁰4s²4p¹
Electronic configuration of Ge is [Ar] 3d¹⁰4s²4p²
After 1st ionisation , Ga  becomes [Ar] 3d¹⁰4s² and becomes stable . Its
 2 nd ionisation requires higher amount of ionisation energy. In case of Ge , there are 2 electrons in outermost orbital so it becomes stable after ionisation of 2 electrons. 
 
        
                    
             
        
        
        
The best answer to your question would be B:those who could not be broken down by physical means.