Answer:
The graph illustrating such a phenomenon will show a sharp curve in upward manners in the beginning but then will  grow downwards as the predation increases.
Explanation:
When a rabbit population is introduced in a habitat, the new habitat will have abundant food for the rabbits. As a result, the population of the rabbits will grow at a much faster rate and hence the graph will move sharply upwards in the beginning. But with the passage of time, the predators of the rabbits will also increase due to the abundance of their preys. More predators will feed on more rabbits and hence a slow decline in the curve will be seen afterwards. 
 
        
                    
             
        
        
        
B. Convection
The heat causes the ocean water movement to continuously circulate around the globe
 
        
                    
             
        
        
        
An independent variable is a variable which change is not affected by that of another variable. By process of elimination you can take out B and C. An independent variable can also change so that takes out A. That leaves D.