Kaylin had morning sickness during her pregnancy and each time she entered the lobby of her building, the potpourri near the elevator added to her nausea. Now the baby is three months old, but when Kaylin stands by the elevator with the baby, she feels a wave of nausea. The nausea from the lobby is

Conditioned Response

Explanation:

When a neutral stimulus is paired with a learned stimulus, it produces a conditioned response. The potent stimulus is a previously learned stimulus which when paired with some neutral scenario, it may trigger a response which is spontaneous. In this scenario, the baby is familiar to this stimulus of morning sickness and vomiting when she was in the mother's belly. Hence, when the baby experiences a similar set-up i.e. the lobby paired with a previously potent stimulus i.e. morning sickness, resulted into a conditioned response. Hence, the neutral stimulus when paired with a conditioned stimulus produces a conditioned response.

answer: the first option is not an affect of aging. so the first option is the answer. (secondary sex characteristics appear)