<prompt> True regarding osteosarcoma is -Occurs because of proliferation of osteoclastsSunray appearance in X-ray indicates new bone formationAffects mainly males in 5th or 6th decadeLymphtic metastasis is most common  <response>: Osteosarcoma arises from primitive bone forming cells.Sunray appearance and Codmans triangle indicate periosteal new bone formation.Osteosarcoma occurs in childhood or young adult 10-25 years.Blood metastasis is most common not lymphatic. 