You are presented with the question "A plant requires what to grow?" and the following answer choices: 
- sunlight
 - freezing rain
 - water floods
 - soft voices
 - food supply
 - Energy.
 - salt and water.
 - direct energy

Now knowing that aplant requires nutrients to grow and nutrient density is the nutrient to calorie ratio of the food supply, choose the best answer.


 

     food supply    