Final answer:
Joining the cross-country team and discussing uniform accommodations with the school's athletic department is the best option for Elizabeth to engage in high school sports while adhering to her religious clothing requirements.
Step-by-step explanation:
For Elizabeth, who wants to participate in high school sports while respecting her religious beliefs of wearing skirts or loose-fitting knee-length bottoms, the best option seems to be joining the cross-country team and wearing the appropriate uniform. Although the details concerning the uniform are not specified, cross-country uniforms often include options that are more flexible and can accommodate longer shorts or leggings, which could align with her clothing requirements.
It is also advisable that Elizabeth engages in a dialogue with her school's athletic department to discuss her clothing needs. This conversation can lead to a better understanding and potentially to the development of a mutually agreeable solution that respects both Elizabeth’s cultural-religious beliefs and the team’s requirements.
Furthermore, considering legal precedents like the case of Elauf, schools, and teams should be willing to accommodate an individual's religious practices as long as it doesn't cause undue hardship or affect the performance and safety standards of the sport.