Answer:
D decrease crop production
Explanation:
The phenomenon in which behaviors that are conditioned only sometimes, thus causing them to be more resistant to extinction, is known as PARTIAL REINFORCEMENT.
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.