question: Collar cells have _ that trap the particles.
choices.text: flexible keratin protection Vibrissae flagella cartilage tissue antigens
choices.label: A B C D E F G H
fact2: Some cells have tiny hair-like fibers that are called flagella.
combinedfact: Collar cells have flagella that trap the particles.
formatted_question: Collar cells have _ that trap the particles. (A) flexible (B) keratin (C) protection (D) Vibrissae (E) flagella (F) cartilage (G) tissue (H) antigens