Answer;
One can infer that membrane transport proteins are required in order for neurons to fire.
Explanation;
Transport proteins are proteins that transport substances across biological membranes. Transport proteins are found within the membrane itself, where they form a channel, or a carrying mechanism, to allow their substrate to pass from one side to the other.
-Transport proteins transport materials such as; ions such as sodium and potassium; sugars such as glucose; proteins and messenger molecules; and many more. In neurons, they  play a fundamental role in the functioning of nerve cells. These transporters, a third class of membrane transport proteins, move a wide variety of ions and molecules across cell membranes.
 
        
             
        
        
        
Answer:
Mining
Explanation:
 The other three natural ways of helping replenish the environment.
 
        
             
        
        
        
That's D. Viral Reproduction. 
It's not A cuz those are not bacteria
It's not B cuz diffusion deals with passive transport across membranes
It's not C cuz gamete formation deals with sex
 
        
             
        
        
        
Is it not to store and transmit genetic info ?
        
             
        
        
        
I believe the substrate for lactic acid formation would be A. Glucose