Final answer:
The anterior oblique subsystem consists of the Internal oblique and External oblique muscles, which work together for trunk rotation and stability.
Step-by-step explanation:
The anterior oblique subsystem includes muscle groups that work together to provide rotational stability and movement to the trunk. According to the provided material, the anterior oblique subsystem would consist of the internal oblique and the external oblique muscles, as these two muscle groups are arranged perpendicular to each other and contribute to the complex movements and stabilization required for trunk rotations. Therefore, the correct pair that forms the anterior oblique subsystem would be a combination of 1) the Internal oblique and 2) the External oblique muscles.