Question

what are cross - bridges? the connections between the myosin tails and the z - discs. the connections between the actin filaments and the z - discs. the connections between the troponin and tropomyosin. the connections between the actin filaments and the m - line. connections between the myosin heads and the actin filaments.

Explanation:

Cross - bridges are formed when the myosin heads on the thick myosin filaments bind to the thin actin filaments during muscle contraction. This interaction is crucial for muscle movement.

Answer:

Connections between the myosin heads and the actin filaments