Answer:
D.
Explanation:
The immune system lowers the chances of bacteria, viruses, and diseases entering your body
 
        
             
        
        
        
Ocean floor is much more denser than the continental crust that's why the oceanic crust subduct rather than the continental crust
        
             
        
        
        
Answer:  An extra cytoplasm enhance survival of a developing oocyte in such a way because cytoplasm serves as a reservoir of lipids, polysaccharide and lipids for the developing embryo.The more the cytoplasm content, more will be the nutrients for the developing embryo. The cytoplasm forms the yolk and provides nourishment to the developing embryo. As we know that the developing embryo requires more nutrition and the main source of nutrition is cytoplasm because the sperm has no reservoir of its own to provide nutrition to embryo. 
Thus, an extra cytoplasm enhance the rate of survival of a developing oocyte.