Fact 1: Flatworms belong to the phylum Platyhelminthes.

Fact 2: Flatworms are bilaterally symmetric.

Given the two facts above, answer the question "What does the phylum Platyhelminthes usually have?" with the following options: 
- resistance
 - Veins and arteries.
 - Leptospirosis
 - sensory neurons
 - bilateral symmetry
 - parasites
 - food and shelter
 - aerobic capacity


 

     bilateral symmetry    