The answer would be -> b. incorrect
        
             
        
        
        
The quartz is more resistant to abrasion and chemically more resistant than the feldspar.  The result is that the quartz remains in the stream but the feldspar breaks down to clay or is dissolved. 
(this is from coursehero.com)
 
        
             
        
        
        
Human environment interaction are essentially the ways in which humans affect their environment and how they are affected by their environment. In Italy examples of this could be Italians who fish the Mediterranean coastal waters. Other examples could be Italians who farm or Italian factories which release pollutants into the environment. Any number of events could count as human environment interactions. 
        
             
        
        
        
(long term) <span>forecast are usually less accurate than (short term) forecast.</span>
        
                    
             
        
        
        
It means to guess/round a number.