A is incorrect. Eating nothing but fruits will not provide you with the right amount of carbohydrates and proteins everyday. C is incorrect. It is not enough that we eat one of each food group since we have target calories per food group. D is incorrect since calcium is not only what our body needs. B is correct, we have target number of calories each day in our diet.
        
             
        
        
        
The answer is b, it can guide treatment of cardiac disease
        
                    
             
        
        
        
May be batteries because we need battery for our torch light which may be helpful during emergency