This textbook contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things. This material should be approached with an open mind, studied carefully and critically considered.
Evolution is a fact, backed by overwhelming scientific evidence; however, I am not sure I agree that the stickers represent the promotion of religion and the violation of the constitutional principle of separation of church and state, as is being suggested. Nevertheless, the stickers were placed to placate parents who believe in Creationism.
Unlike Evolution, Creationism has no basis in fact whatsoever; therefore, it is wholly unsuitable for it be taught in schools. The same can be said for the theory of Intelligent Design, which is just a pseudo-scientifically sanitized version of Creationism.