Final answer:
The incident in The Metamorphosis that suggests Gregor's new physical form is disgusting to the family is when Grete opens a window before entering Gregor's room.
Step-by-step explanation:
The incident in The Metamorphosis that suggests Gregor's new physical form is disgusting to the family is when Grete must open a window before she can stand to be inside Gregor's room. This suggests that the smell or appearance of Gregor in his new form is repulsive to them. Opening the window is a way for Grete to create some distance and alleviate the discomfort caused by Gregor's transformed state.
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