Final answer:
The muscles involved in thigh flexion include the rectus femoris of the quadriceps group, which flexes the thigh at the hip, and the biceps femoris of the hamstrings group, which flexes the knee.
Step-by-step explanation:
The muscles responsible for thigh flexion are those found in the anterior compartment of the thigh. The rectus femoris, which is part of the quadriceps femoris group and is located on the anterior aspect of the thigh, plays a crucial role in flexing the thigh at the hip. Therefore, the answer to the question is A) Rectus femoris and biceps femoris. However, it should be noted that while rectus femoris is involved in thigh flexion, the biceps femoris, which belongs to the hamstring group, is primarily involved in flexing the knee. If the question specifically asks for muscles involved in thigh flexion at the hip, then biceps femoris would not be a correct answer as it participates in knee flexion, not thigh flexion.
The muscles responsible for thigh flexion are the rectus femoris and the biceps femoris. The rectus femoris is part of the quadriceps group located in the anterior compartment of the thigh, while the biceps femoris is one of the muscles in the hamstrings group in the posterior compartment of the thigh.