Biotic Factors are any living components that affect other organisms, and since soil is not alive (soil is an abiotic factor) then you can eliminate A., B., and C. D is the answer choice that has only biotic examples. 
        
                    
             
        
        
        
Answer:
: A decrease in pH is too acidic compared to optimum pH for amylase activity.
 
        
             
        
        
        
The allele combination for a female carrier is XRXr
 
        
                    
             
        
        
        
Answer:
Biology is not a hard class however it does require memorization and comprehension of certain topics. I recommend that you read over the chapters and make flashcards and test yourself. You can also ask your teacher for help. There are many videos available that do a great job at explaining each topic in biology. In addition, there are various websites that can also provide information. You should make study groups with your classmates as it is a more fun and effective way of studying. 
 
        
                    
             
        
        
        
Answer:
D, There is no Weathering on the moon
Explanation:
The moon doesn't have an atmosphere therefore there cannot be any Sedimentary rocks on the Moon.