Final answer:
Ochako Uraraka from My Hero Academia did not activate her Zero Gravity quirk when pinning Toga due to her control and deliberate choice in the midst of combat, which allows her to touch others without triggering the quirk's effect.
Step-by-step explanation:
The question pertains to a specific event in the anime or manga series My Hero Academia, where Ochako Uraraka does not activate her Zero Gravity quirk when she pinned down Himiko Toga. In the series, Ochako's quirk allows her to make any object she touches with her fingertips become weightless. However, for her quirk to activate, she must consciously will it and often uses a 'release' gesture to deactivate the effect. During combat, she has control over her quirk activation, which means she can engage in physical confrontations like pinning an opponent without affecting them with her quirk. Therefore, Ochako did not activate her quirk likely due to her tactical decision and control over her quirk's activation.