The question is incomplete. The complete question is :
A platypus foraging for prey can detect an electric field as small as 0.002 N/C.
-To give an idea of sensitivity of the platypus's electric sense, how far from a +80nC point charge does the field have this magnitude?
Solution : 
Given electric field,  E = 0.002 N/C
Charge, Q = + 80 nC

or 
     
    R = 600 m
This is the distance of the charge from the point of observations.
 
        
             
        
        
        
Answer:
a water bottle. 
Explanation:
a water bottle drains an area of land, just pour a water bottle on a small land on the surface of the earth it'll be called drained.
 
        
             
        
        
        
Density is directly proportional to mass. So if there's less matter inside object, its density will also reduce.
        
                    
             
        
        
        
Acceleration is the
rate of change of velocity, a body moving with uniform velocity does not
possess acceleration at all i.e. acceleration is zero
 
        
             
        
        
        
if there were no invention of machines then life would have been more difficult and simple works could be hard to do. Even now we are using our phones, sitting in a AC room interacting to eachother from different places. without the invention of machines simple things like transportation would have been difficult. There would be horses and donkey for the transportation. There would be no electricity,no internet, no transportation, not even c computers or mobile etc. The market for business will be smaller, the knowledge and news about world would be less. 
so the problem would have been bigger than we can imagine. But one thing is that nature could survive lot more compared to what we have done till now by destroying nature.