Answer - B
Reason - Since the area is in the tropics there will be time to time heavy precipitation, which over time the decomposed nutrients will get washed down into a run off and depleted.
        
             
        
        
        
The process that tend to reduceb the variety within a population is called B. Random fertilization.
        
             
        
        
        
Temperate evergreen forests, coniferous, broadleaf, and mixed, are found largely in the temperate mid-latitudes of North America, Siberia, Canada, Australia, Africa, Scandinavia, Indonesia, Malaysia, Amazon and Orinoco basins of South America, Himalayas and western ghats of India and Andaman and the Nicobar Islands.
        
             
        
        
        
The answer to ur question is gametophyte....
Hope This helps u....!!!