Answer:
I believe it is A, but I could be wrong. 
Explanation:
I think this, because when it says, "Other, less useful, versions of the genetic code were eliminated gradually throughout the course of evolution", I think it referencing to the fact that all animals and etc, are made up of common codes, and how over time, through evolution, certain codes were eliminated, because creatures were evolving.
 
        
             
        
        
        
Answer:   A
Explanation:
Carrying Capacity because it is showing how many ferns the rainforest can support.
 
        
             
        
        
        
Answer:
A, it doesn't matter where they were grown or the cost it matters but what's in the product and how much of what ingredients in it.
 
        
                    
             
        
        
        
Yes the o horizon layer is where most plant life is like in a forest it where all the roots of grass is