There are eight books kept on over the other. Two books are on Professional ethics, two books on SFM, three books on Environmental science and one book on Politics. Counting from the top, the second, fifth and sixth books are on environmental science. Two of them are between the books on SFM. One Environmental Science book is between two books on Professional ethics while the book above the book on Politics is a book of SFM. If the books are partitioned as two rows by taking four from the top, which of the books will be at the bottom?