"What is human nature?" is the key question psycology seeks to answer
        
             
        
        
        
Answer:
B
Explanation:
 soil being depleted to nitrogen due to high runoff
 
        
                    
             
        
        
        
Answer:
That would be option D. A motor. 
Explanation:
 
        
             
        
        
        
B. The Hubble Space Telescope
        
                    
             
        
        
        
Answer:
In gram-negative bacteria, the thin layer of peptidoglycan is surrounded by an outer membrane made of phospholipids, lipopolysaccharides, and proteins. This statement accurately describes specific bacterial cell walls. 
Explanation:
The Gram- negative bacteria constitute of an outer membrane which is richly made up of lipopolysaccharides, phopholipids and proteins. The lipopolysaccharides function mainly as a virulence factor and are involved in causing variety of diseases in animals. 
Gram- negative bacteria can be seperated from gram- positive bacteria mainly because of the thickness of peptidoglycan and by the presence of the outer membrane of Gram- negative bacteria. The outer membrane is absent in Gram- positive bacteria.