Final answer:
The correct options are a and b. The issue with the front leg of the foal being bowed affects the Skeletal system and the Muscular system.
Step-by-step explanation:
The issue with the front leg of the foal being bowed affects the Skeletal system and the Muscular system. When the leg is bowed, it means that the bones and muscles in the leg are not aligned properly, resulting in the leg appearing curved rather than straight.
This misalignment can make it difficult for the foal to walk or run properly. The Skeletal system provides the framework for the body and includes the bones and joints. The Muscular system works in conjunction with the Skeletal system to allow movement and provide support. In this case, the issue with the leg is caused by a problem in both the bones and the muscles, making it a combined issue of the Skeletal and Muscular systems.