Final answer:
The calcaneus is the largest bone of the foot's tarsal bones and forms the heel, and the lower limb consists of 30 bones, which include the femur in the thigh and the tibia and fibula in the leg.
Step-by-step explanation:
The calcaneus is the largest of the tarsal bones and forms the heel of the foot. It plays a critical role in the structure of the foot and the body's ability to walk and run.
The lower limb is divided into three sections: the thigh, the leg, and the foot, containing a total of 30 bones. The thigh houses the femur, the longest bone in the body. In the leg, two bones, the tibia and fibula, are present, with the tibia being the larger, weight-bearing bone.
The foot is composed of the tarsal bones, among which the calcaneus is the largest, the metatarsal bones, and the phalanges of the toes. The bones of the lower limb, especially the femur and tibia, are designed to be thicker and stronger than those in the upper limbs to support the body's weight and withstand the forces during locomotion.