How does stretching primarily contribute to flexibility?

Stretching primarily contributes to flexibility by enhancing the elasticity of muscles and tendons. When you engage in stretching exercises, the muscle fibers and tendons are gradually lengthened, which improves their elasticity. This means that they can stretch further and return to their original shape more effectively. Enhanced elasticity allows for a greater range of motion in the joints, which is crucial for various physical activities and can help improve overall performance in sports and activities.

The other options do not align with the primary function of stretching in relation to flexibility. Increasing muscle mass pertains more to strength training rather than flexibility. Preventing muscle contractions is more related to muscle relaxation and neuromuscular control rather than the direct mechanism through which flexibility is improved. Lastly, cardiovascular endurance is associated with aerobic fitness and is not directly connected to the effects of stretching on muscle and tendon elasticity.