请教gwd 一道逻辑题

zhaozihan

Which of the following most logically completes the argument ?

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.Agronomists studying the  herb have discovered that it produces large amounts of histidine,an amino acid that ,in test-tube solutions ,renders these metals chemically inert .Possibly,therefore,the herb'shigh histidine production is what allows it to grow in metal-rich soils,a hypothesis that would gain support if _

key :the concentration of histidine in the growing herb declines as the plant approaches maturity 如何理解答案 谢谢

lanfeifeiYY

答案等于是把原文反说了， 这个herb成熟后h物质减少，那么说h物质确实是帮助herb 成长的

zhaozihan

大侠 我发现我发的每道题你都会耶 可不可以留个你的QQ我想好好地请教请教你