Protection: By protection, we mean to say that they cover and protect many soft organs/ tissues in the body. They protect the control panel of the human body called "brain" in the form of protective sheath of skull. They form the spinal cord which helps the body stand erect. The liver, heart, digestive system etc are also covered and protected by the rib cage. As they are tough they act as a really good shock absorbents. Especially in case of accidents, these act as a real savior.
Locomotion: Both in humans and animals bones are the essential components for locomotion or transport. The fore limbs and hind limbs are the made up of bones. Almost all animals and humans depend on their limbs for their food and transport. The pelvic girdle, pectoral girdle and muscles along with these limbs help in locomotion and various other activities.
Also many of the body muscles are attached to bones. The body muscles and bones are linked to each other with special joints called tendons and ligaments. These muscles along with the proper framework bones help in transport.
In birds the bones in the forelimbs are suitably modified for flight in the form of wings and animals it is modified for walking on land.
