The study found that the 20 to 39-year-old group is more enthusiastic about using sports applications in smartphones, the main reason is that most of this group has already participated in work, and sub-health is more common in this group, so more and more Many white-collar workers and young people pay more attention to physical health; at the same time, the obesity rate of young people is relatively high, and young people's pursuit of beauty is far more than that of middle-aged and elderly people, so they care more about sports; in addition, the user group of this age group is also more Familiar with smartphone operation. Which of the following, if true, would most weaken the above findings? ['Many young people are addicted to games in their smartphones.', 'Many young people work overtime for long periods of time.', "Young people's lack of exercise can easily lead to sub-health problems.", 'Contemporary young people are too rich in nutrition and overweight.']