Final answer:
The posterior muscles of the leg are responsible for plantar flexing the foot and flexing the toes, involving both superficial and deep posterior compartments.
Step-by-step explanation:
The posterior muscles of the leg primarily have two functions: plantar flexion of the foot and flexion of the toes. The superficial posterior compartment includes the gastrocnemius, soleus, and plantaris muscles, which are primarily responsible for plantar flexion of the foot. Meanwhile, the deep posterior compartment houses muscles such as the tibialis posterior, flexor digitorum longus, and flexor hallucis longus, which assist in plantar flexion and also play a role in flexing the toes. Therefore, the correct answer is that the posterior muscles of the leg plantar flex the foot and flex the toes.