I am opting ES for the upcoming exams which are due to be held. I am preparing from Advanced's Environmental Sciences of M. Imtiaz Shaid. Although this book is written in-depth, but it has some additional topics when compared with the revised syllabus. The quality of the knowledge is good and the writer has preserved the language of subject as well. Internet, on the other hand, will be useful to prepare for this subject.

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Ideals are peaceful. History is violent