There are some grammatical mistakes in this line which should be removed while the comment S5 is not similar to that line as this line identifies “causes of obesity” while S5 identifies “other problems that may be occurred due to obesity”.
S2
As introduction should include some lines about what your essay or paper tells and include. Therefore, these sentences are correct. But, in order to revise this paper, you can change the wording of these sentences by giving them a formal look like “In this paper we discussed Obesity as a problem, factors that affect obesity especially ...