Expertssssss! Please please help resolve the confusion.
If the concentration of histidine declines on maturity, that should mean that the plant starts to die whereas the agrument doesnt say so atall.
My logic for picking up option D was:
Since histidine makes the metal inert, so, once this particular herb is cultivated in the soil rich in toxic metal, the herb would turn the metal in soil inert making it fit for cultivation of other plants. So, I picked option D. Please tell me the flaw in my reasoning.
thanks in advance.