Some people think that the older a person is, the more free radicals accumulated in the body, the more damage caused by oxidation, and eventually aging and death. Proanthocyanidins contained in grape seed extract can effectively remove free radicals in the body and protect the human body Cells and tissues are protected from oxidative damage by free radicals. Therefore, eating grape seed extract can prevent oxidation and prevent aging. Which of the following, if true, would most weaken the argument? ['Polyphenols contained in grape seed extract are easy to cause liver damage.', 'Daily foods such as various vegetables and fruits also contain more antioxidants.', 'There is no difference in free radical concentration in young, middle-aged and elderly people.', 'Dismutase in the body will combine some free radicals to reduce the damage caused by its oxidation.']