Answer D because humans can effect the way of life in an ecosystem and things like climate can effect them too
        
             
        
        
        
Immune System is the system that consists of proteins and cells.
 
        
             
        
        
        
Answer:
good question, you don't. Or simply wait untill you finish choking bart
 
        
             
        
        
        
The topsoil is the upper and outermost layer of soil, usually the top 2 inches to 8 inches. It contains the highest concentration of organic matter and microorganisms. Topsoil is used as the medium for all plant growth, whether it is a lawn, garden or prairie.