GRE Text Completion: JiJing 1373-GRE填空机经1373题 - 6I3WVJFED82N53T2A

It remains a mystery how Theobroma cacao, which scholars believe originated in lowland Amazonia, was introduced to tropical Mesoamerica. It must have been a (i)____________ process: cacao trees do not easily sprout from seed, need years to mature, and grow only in humid lowland forest. Moreover, in a tropical climate, cacao pods spoil quickly, rendering their transport from lowland Amazonia tropical Mesoamerica in a single journey by foot or canoe (ii)____________. A. clandestine B. unlikely C. protracted D. redundant E. spontaneous F. expeditious