Answer:
cation exchange
Explanation:
Based on the information provided within the question it can be said that this would most likely be achieved by cation exchange chromatography. This is mainly due to the fact that Nickel (Ni) is a cation and that Histidine contains an imidazole side chain that is positively charged. Therefore since this is using a nickel based resin then it will be best achieved through cation exchange chromatography.
Answer: The Mayan civilization was not only vast but also developed beyond its time. This included the temples and pyramids that were difficultly engineered. The Incan civilization is credited with the development of roads and trade routes, making them a significant "nation" especially considering the age (of time). The Aztec civilization developed astonishingly accurate measurements of time and astronomy. These three civilizations are regarded as "Great" because of their extraordinary advancements (given the time period).
The answer to this is letter A.
