Some potatoes of the Andes contain ……………… known as glycol-alkaloids, poisons that induce stomach pains, vomiting and even death.
If you omit the phrase, known as glycol-alkaloids, this question is simple one similar to the last one. The missing word must stand for poisons that induce stomach pains, vomiting and even death. Can you think of a single word that has this meaning?
Among the given choices, toxins meaning poisons is the obvious choice.
So, the answer is (D).
GRE-Model Questions Index