You are presented with the question "what do male dogs use in their urine to mark their territory?" and the following answer choices: 
- feces
 - layers of fat
 - natural aphrodisiacs
 - food
 - Something coming from a gland
 - Chemical energy
 - cats
 - hydrocarbons

Now knowing that male dogs use pheromones in urine to mark their territory and pheromones are natural aphrodisiacs, choose the best answer.


 

   natural aphrodisiacs      