Fact 1: Male dogs use pheromones in urine to mark their territory.

Fact 2: Pheromones are natural aphrodisiacs.

Given the two facts above, answer the question "what do male dogs use in their urine to mark their territory?" with the following options: 
- feces
 - layers of fat
 - natural aphrodisiacs
 - food
 - Something coming from a gland
 - Chemical energy
 - cats
 - hydrocarbons


 

   natural aphrodisiacs      