mslancaster

the herb’s high histidine production is what allows it to grow in metal-rich soils
结论不就是针对the herb么？！
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.这句话主要也就是说the herb能在含有毒金属的土壤中thrive,怎么就能把注意力转移到others of the closely related group of plants上呢？它们产生histidine，the herb也能产生 histidine，它们都有 histidine，都能在有毒金属土壤中thrive，就能证明是 histidine造成的了？~~~不太懂还是。。。还是说C想证明the herb in test-tube solutions产生的histidine在自然环境中也能产生？~~那么D似乎更直接一些啊，直接针对the herb...

mslancaster

Guys, this is a sufficient assumption question. All you need to do is to plug in each answer choice and see if you can complete the conclusion in the stimulus.

Try it.