Which of the following describes the role of the semitendinosus muscle?

The semitendinosus muscle plays a crucial role in both extending the hip and flexing the knee, which is why this answer is correct. This muscle is one of the hamstring group located at the back of the thigh. When it contracts, it allows for the extension of the hip joint, which is the movement of bringing the thigh backward, while simultaneously enabling the flexion of the knee joint, where the lower leg moves toward the thigh. This dual capability is essential for various activities, including walking, running, and jumping, as it helps power movement and maintain balance during locomotion.

The other choices do not accurately describe the semitendinosus. While some muscles are involved in actions such as abducting the hip or solely stabilizing the patella, these functions are not part of the role of the semitendinosus. This highlights its specific involvement in the movement of the hip and knee rather than any functions related to abduction or patellar stabilization.