Our objective, however, indeed our obligation, is to present sound science. Creationism has absolutely no basis in science and we do not, therefore, treat it as a scientific explanation for the origin or diversity of life on earth. Whether you choose to accept it or not, the evidence for the relatedness of all species by descent with modification is overwhelming. Some of this evidence is derived, as you indicate, from the fossil record. Some is derived from fields such as comparative anatomy and developmental biology, which compare structures, functions, and developmental programs among living representatives of closely related species.
Additional evidence comes from cell biology, biochemistry, genetics, and molecular biology.
That history is written in the genes in every cell in your body, and it tells the story of biodiversity produced by descent with modification, with natural selection as the prime mover over enormous expanses of time. You may choose to embrace other explanations, but again, I caution you to be aware of those that meet the requirements of science and those that do not. I have provided a number of enclosures that may help you understand some of the perspectives I have outlined above. I also have sent a copy of this letter and its enclosures to the biology department at your school so that the biology teachers there can read my response to your concerns. This may help them address questions from your classmates, who, you state, share your concerns.