Trade and exchange across cultural lines have played a crucial role in human history being perhaps the most important external stimuli to change. External stimulation has been the most important single source of change and development in art, science, and technology. Perhaps this goes without saying, since no human group could invent by itself more than a small part of its cultural and technical heritage. A) Identify and explain one change or development prior to 600ce that would support the author’s assertion in the passage above. B) Identify and explain two changes or developments prior to 600ce that would challenge the author’s assertion in the passage above.