An argument is only as solid as the logic it is formed on. All Animals Are Equal by Peter Singer is not valid inasmuch as he does not present sufficient cause or a logical order to his argument. No additional sources are listed. Endnotes are included. A 7 page paper outlining the evolution of the lung from the primitive lungfishes to mankind.
Bibliography lists six sources.
A 7 page outline of the characteristics mammals have in common with their predecessors the reptiles and the features which distinguish them. Bibliography lists five sources.