英语问题关于thesis statement 的我这里有两个不合格的thesis statement请问如何改才好1：i think genetically modified food is terrible.2:public transprotation has some advantages and disadvantages.

1. I think GM food is terrible because producing GM food causes environmental hazards, GM food increases health risks, and GM food is too costly.
2. Public transportation has the advantages of being environmentally friendly, economical, and avoiding traffics (1.desinated lane for buses through. 2. subway) and the disadvantages of limited and unprivate spaces(have to share the space with others that you probably don't feel comfortable with and sometimes there's just no room for you in rush hours), inflexiblility (eg. you might want to stop off at the bank, or swing by a convenient store for beakfast before going to the workplace or school), and concusming extra energy and time of walking to a subway station or a bus shack (comparing with the distance of getting your car or bicycle)

Modified food，I think,in the area of genetics,is terrible.
It must be noted that public transprotation is a double-edge sword。

1.I think GM food is terrible because producing GM food causes environmental hazards,GM food increases health risks,and GM food is too costly.
2.Public transportation has the advantages of being environmentally friendly,economical,and avoiding traffics (1.desinated lane for buses through.2.subway) and the disadvantages of limited and unprivate spaces(have to share the space with others that you probably don't feel comfortable with and sometimes there's just no room for you in rush hours),inflexiblility (eg.you might want to stop off at the bank,or swing by a convenient store for beakfast before going to the workplace or school),and concusming extra energy and time of walking to a subway station or a bus shack (comparing with the distance of getting your car or bicycle)