Solar energy because of the sun's rays
        
                    
             
        
        
        
Mitochondria are unusual organelles. They act as the power plants of the cell, are surrounded by two membranes, and have their own genome. They also divide independently of the cell in which they reside, meaning mitochondrial replication is not coupled to cell division. Some of these features are holdovers from the ancient ancestors of mitochondria, which were likely free-living prokaryotes.
        
             
        
        
        
Doctors try to remove tumors from the body to prevent it from spreading and affecting other parts of the body.
        
                    
             
        
        
        
D - birth control is the most widely accepted method