Answer:
The correct answer is option A: they are isotopes.
Explanation:
From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.
Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.            
The mass number is given by:               
 
 
Where <em>n</em> is the number of neutrons and <em>p </em>is the number of protons. 
For atom X and atom Z we have:

 
 
Hence, they have a different mass number.  
We know that the element with 7 protons is nitrogen. The first isotope is  and the second isotope is
 and the second isotope is  . Both isotopes are stables (they are not radioactive).
. Both isotopes are stables (they are not radioactive).  
 
Therefore, the correct answer is option A: they are isotopes. 
I hope it helps you!                                                           
 
        
             
        
        
        
Answer:
a) yield strength
    
b) modulus of elasticity
strain calculation
 
strain for offset yield point
 
                               =0.0046-0.002 = 0.0026
now, modulus of elasticity 
   
 
     = 184615.28 MPa = 184.615 GPa
c) tensile strength
  
d) percentage elongation
 
e) percentage of area reduction
  
                             
 
        
             
        
        
        
Thiết bị không phải nguồn điện: 
Đáp án D
 
        
             
        
        
        
Answer:
Rhinoceroses are odd-toed ungulates native to sub-Saharan Africa and southern Asia, though all five living species have hugely contracted in range and number due to the influence of humans. Despite their titanic, tank-like bulk, rhinos can be amazingly swift: The fastest may reach at least 50 kilometers per hour (31 mph).
Explanation:
sana makatulong
 
        
             
        
        
        
The Greek philosopher Aristotle and the Roman Catholic Church also believed the sun revolved around the earth. In 1543, Nicolaus Copernicus<span> published a new theory stating the earth revolves around the sun. This is known as the Copernican theory.</span>