Cation-exchange chromatography is used when the molecule of interest is positively charged, the stationary phase is negatively charged and positively charged molecules are loaded to be attracted to it. So, the amino acids with negative charge will elute the first. Glutamate, leucin, arginine is the order of elution because of their pI values ~3, ~6 ~10.
I would say B) <span>The shoot is positively phototropic and negatively gravitropic; the root is positively gravitropic and negatively phototropic.
This is because the shoot of the plant is attracted towards the sun, as the chloroplasts in the leaves need sunlight to make food. As well, the roots are attracted downward to absorb more water and minerals from the sun.
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