cleaning its ears sleeping on a chair sharpening its claws meowing when it is hungry
I gave my students this multiple choice question: Which characteristic of a kitten is an acquired trait due to environmental influences?

Only one answer is correct among these 4 choices:
- cleaning its ears
- sleeping on a chair
- sharpening its claws
- meowing when it is hungry

Could you tell me which one is correct?

sharpening its claws