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Dear Student,

Parts 3 and 4 are tarsals and phalanges respectively.
Synovial fluid is present in the knee joint (hinge joint).
Parts 1 and 2 are femur and tibia respectively and their corresponding bones in forelimbs are humerus and radius.
Human skeletal system is constituent of bones and cartilages. It provides movement of the body and also bones and few cartilages act as connective tissues.
Rough sketch of thoracic vertebra.

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