Answer: The author makes a strong opening statement, but should avoid "I think.. ." Let the statement stand on its own merits. "Chemicals are deadly." It is then evident that this is an over-generalization.
Not all chemicals are deadly. Many are beneficial. It may be true that her brother is affected by some of the chemicals in the food he eats, and it would be better for him to eat more natural foods with fewer chemical additives.
The reference to "a study said. . ." would be much more credible if the author had named the source of the study, or the credentials of the researcher who did the study. It would be good to specify "insecticides" or "pesticides" responsible for killing bees.
The conclusion is a good call to action, but again, too general. I like the alliteration of "kick the chemicals to the curb" but there might be a way to say "Be thougthtful about the chemicals you use, and the additives you consume; when possible, do yourself and the environment a favor and kick chemicals to the curb!"
Step-by-step explanation: