Final answer:
Classicism is the term for the long-lasting, traditional quality of art that idealizes the human body in sculptures like Discus Thrower by Myron. It refers to the adherence to ancient Greek and Roman artistic principles, which emphasized balance, harmony, and idealized representations of the human form.
Step-by-step explanation:
The term for the long-lasting, traditional quality of art that idealizes the human body in sculptures like Discus Thrower by Myron is Classicism. Classicism in art refers to the adherence to ancient Greek and Roman artistic principles, which emphasized balance, harmony, and idealized representations of the human form. These sculptures were created during the High Classical period and are known for their lifelike and realistic depiction of human anatomy.