Fact 1: Ants communicate with chemicals called pheromones.

Fact 2: Physiologically, ants leave a trail of pheromones, which other ants then follow.

Given the two facts above, answer the question "How do ants communicate to other ants to encourage them to follow?" with the following options: 
- Skywriting
 - Electrical energy
 - Using a phone to communicate
 - Leaving a written communicatio
 - Something coming from a gland
 - By wind and rain
 - Chemical energy
 - Leaving chemical trails


 

        Leaving chemical trails 