All of the followings may be the outward signs of aging EXCEPT _____.

Đáp án D

Thông tin nằm ở đoạn 1: “The most familiar outward signs of aging may be seen in old people, such as the graying of the hair and the wrinkling of the skin. Signs of aging in a pet dog or cat include loss of playfulness and energy, a decline in hearing and eyesight, or even a slight graying of the coat. Plants age too, but the signs are much harder to detect.”