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
A:
bilateral symmetry