Final answer:
The sculpture that claimed a visible space for the anti-war movement and poked fun at the solemnity of the plaza is Lipstick (Ascending) on Caterpillar Tracks by Claes Oldenburg.
Step-by-step explanation:
The name of the sculpture that claimed a visible space for the anti-war movement and poked fun at the solemnity of the plaza is Lipstick (Ascending) on Caterpillar Tracks. It was created by the artist Claes Oldenburg and is made of Cor-Ten steel, steel, aluminum, and cast resin. The sculpture gained attention for its bold and unconventional design, which satirized the seriousness of the traditional plaza setting.