How does the antagonistic muscles keep the body upright and straight?

Antagonistic muscles work in pairs to maintain posture and keep the body upright by contracting and relaxing in opposition to each other. For example, when one muscle group, like the back muscles, contracts to straighten the spine, the opposing muscle group, such as the abdominal muscles, relaxes to allow movement and balance. This coordinated action helps stabilize the body's position against gravity. By continuously adjusting the tension in these muscle pairs, the body can maintain an upright and straight posture.