when was his book mentioned above published?
From 1830-1833.
Principles of Geology
Principles of Geology: being an attempt to explain the former changes of the Earth's surface, by reference to causes now in operation is a book by the Scottish geologist Charles Lyell that was first published in 3 volumes from 1830–1833.
how do some chemicals in plants protect them from their enemies Through allelochemicals  that influence the behavior, growth, or survival of herbivores. name some animals/species that fall under the last-mentioned category. White-tailed deer , elephants, zebras, and giraffes. how would this category be defined? A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. where does the term come from? Herbivore is the anglicized form of a modern Latin coinage, "herbivora," cited in Charles Lyell's 1830 "Principles of Geology." who is this person mentioned here? Sir Charles Lyell, 1st Baronet, was a Scottish geologist who demonstrated the power of known natural causes in explaining Earth's history. what are some of his most renowned books? "Principles of Geology" . what did he conclude from studying volcanoes? His conclusions supported gradual building of volcanoes, so-called "backed up-building", as opposed to the upheaval argument supported by other geologists. what were his contributions to the study of glacial features? Lyell proposed that icebergs could be the means of transport for erratics. During periods of global warming, ice breaks off the poles and floats across submerged continents, carrying debris with it, he conjectured. When the iceberg melts, it rains down sediments upon the land.
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Principles of Geology [SEP] Introduction
Principles of Geology: being an attempt to explain the former changes of the Earth's surface, by reference to causes now in operation is a book by the Scottish geologist Charles Lyell that was first published in 3 volumes from 1830–1833. Lyell used the theory of uniformitarianism to describe how the Earth's surface was changing over time. This theory was in direct contrast to the geological theory of catastrophism. Many individuals believed in catastrophism to allow room for religious beliefs. For example, the Genesis flood narrative could be described as a real geological event as catastrophism describes the changing of the Earth surface as one-time, violent events.