After mrs. chanski and her children had themselves to free samples of the cookies being promoted in the grocery store, she felt obligated to buy some, even though they seemed unreasonably expensive. her reaction best illustrates the significance of:

The answer is the reciprocity norm.

Explanation:

This norm states that people feel the need to reciprocate (make up for) other people's actions. It is especially common for positive gestures. For example, if someone gives us a gift, we feel the need to repay it.

This norm seems to be an important factor for a harmonious society, as it reinforces phenomenons such as reciprocal altruism.

b) the planets year length would be longer

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