Birds because they spread seeds
        
             
        
        
        
Solving problems with science means that to solve the problem the scientific method is used. This method includes observing, research, hypothesis , test and conclusion with a help of lot high level theory. 
Without science there is not strict process to follow in order to resolve the problem end get to a solution. 
        
             
        
        
        
Answer:
Net force=120N-90N=30N
30N to the right
        
             
        
        
        
Answer:
your answer it is help to understand this question