Answer:
Option: (D) To identify patterns of diffusion and their effect on the host country.
Explanation:
The geographer purpose of studying the pattern of migration is to look at the reasons for the people leaving their native country and migrating to the host country.
To check the migrant's effects on the host country, it would be useful to divide two groups according to their skills - highly educated and skilled labor. Migration would affect the country because they will help the host country to built-in a good shape by their skills and knowledge.
As a result between the people from the European continent and the people from the North American and South American continents, most of the native populations had died out.
Even though there's the general opinion that the main cause for this were the battles and the killing in them, even though they were numerous and there were casualties, the reason for the mass dying out was totally different, diseases.
The Europeans brought new diseases with them, and the Native Americans were not immune to them, so they spread around them very quickly and they were dying very quickly, which lead to a depopulation of large ares of the continents.
Oxygen, i believe is your answer
hope this helps :)
The annual greenhouse gas index has increased approximately 42% from 1979 - 2017.
