“人们根据自己的信念来选择吃的习惯”，而且还谈了“人们根据食品的生长制作方式来决定选取”，即：We also make choices based on how the products are grown or made. 因而该段的主题应归纳为：People make choices about their eating habits based on what they believe and how the products are grown or made.
该句应改为：Today, there are over 50 clowns, almost all of whom come from Clown College. 这是因为英语中逗号不能用于并列的句子之间。再如：
The car ran into a crowd of people, several of whom were sent to hospital immediately.
I met the sportsmen, two of whom were studying in universities.