- A Myosin
- B Collagen
- C Actin
- D Keratin
Correct answer: C. Actin
Explanation: Actin forms the thin filaments. The thin filament also contains tropomyosin (blocks myosin binding sites at rest) and troponin (Ca2+ sensor that moves tropomyosin to expose binding sites).
Concept context
Types of movement, muscle contraction, skeletal system, joints, and disorders. Important for Class 11 and NEET.