Answer: D) None of the above
Explanation: The subschema differs from the schema in that one denotes the appearance of data in the Database Base Management System (DBMS) while the subschema which is also referred to as the external schema is that subset of the schema is visible or relevant to the user. Thus, It is the view of the database which is visible to an application program. Virtual tables in a database usually represents an object structures like a table which is the result of running certain database commands or functions such as the create table, view, select and so on. Virtual tables are not stored directly in database files.
Answer:
The Europeans, apart from doing their business through the Mississippi and Amazon, brought diseases to the native populations.
Explanation:
When the Europeans started to explore the Americas, they were trying their best to establish the best possible foundations for business and to make a big profit from it. This led to using everything that was at disposal, and the large rivers, like the Mississippi and Amazon, were excellent for easy travel and transportation over long distances. While these rivers served the Europeans very well, it brought tragedy to the natives.
Not always the Europeans were agressive to the native populations, but actually, more often than not they tried to establish good relations with them because in that manner they were able to have greater benefit. Unfortunately, through the interaction, the Europeans transmitted multiple diseases to the natives for which they did not have immune system capable of coping with them. This led to mass dying out of native populations. Both continents were heavily affected by this, and while often forgotten, the Amazon basin, with the new discoveries and what has been written in the exploration books by the Europeans, might have had several million-strong populations, which dissapeared in only a few decades.
I’m pretty sure it’s for their horns?
Need for raw materials because of the plentiful amount that is in Africa, such as gold, diamonds, wood, and coal.
Economic opportunities seems to be the driving factor for migration nowadays. An example of a group of migrants migrating from areas with a lack of economic opportunities to areas with more economic opportunities are Mexican immigrants seeking job opportunities.
