Answer:
C.
Step-by-step explanation:
Simply multiply 50 by 3/8
 
        
             
        
        
        
Photo math works and the answer would be on that app!!
        
             
        
        
        
Answer:
The second step because she distributed within the parentheses without adding the negative sign to 13
 
        
             
        
        
        
Answer:

Step-by-step explanation:
In order to add or subtract numbers in scientific notation, the powers of ten must have the same exponent.  In this caes the diameter of an average human body cell is a power of -4 and the diameter of a plant cell is a power of -3.  In order to add them, we can move the decimal over for the body cell diameter: 

Add the two values: 
 
        
                    
             
        
        
        
Answer:
both
Step-by-step explanation: