“What is the primary structure of bacteria?”

"The flagellum is a key structure in many bacteria enabling motility by acting as a whip-like propeller. Composed of proteins it allows bacteria to navigate environments seek nutrients or evade threats. While not all bacteria have flagella their presence is critical for understanding bacterial behavior pathogenesis and environmental interactions. Studying flagella aids in developing antibiotics and understanding microbial ecology highlighting their significance in microbiology and medical research where bacterial motility influences infection mechanisms and environmental adaptations."