Answer - Theory 
Reasoning - Your best bet and term to describe the evolution by natural selection is theory as to still scientific theory/research is still ongoing and changes can be made in a different direction.
 
        
                    
             
        
        
        
Answer:
 protect coastlines from storms and erosion, provide jobs for local communities, and offer opportunities for recreation.
Explanation:
it helps the world in different ways 
 
        
             
        
        
        
The digestive system breaks down food, the respiratory system takes in oxygen, and the cardiovascular system delivers the oxygen and food to the cells.
        
             
        
        
        
Answer:
The correct answer is it causes immediate pathogen lysis.
Explanation:
The  complement system is a part of innate immune system which is called first line of defense mechanism of our body.
          complement system along with various proteins and enzymes stimulate the phagocytic cells to attack the plasma membrane of foreign pathogen,Which ultimately result in the lysis of foreign pathogen by phagocytosis mechanism.
 
        
                    
             
        
        
        
For example, if the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). ... If the acceleration is great, then the line slopes up steeply (i.e., the slope is great).