Do you mean the most recent migration?
Most recently, Europe has experienced a significant migration from Asia and Northern Africa, with some more specific migrations, such as Turkish Migration in Germany and Austria and I think Somalian migration in Sweden.
Some of the effects is the visibility of Islam in those countries, most visible through female headscarves. Another effect was the shift in food, with more and more Europeans accepting Kebab and Chinese noodles as a form of "fast food". Also, the societies have become less homogenous.
Answer:
Upwelling and Downwelling
Explanation:
The Earth's oceans have differing temperatures and sediment levels. Water with more sediment is usually colder, and thus is more dense and sinks. Water with less sediment is usually warmer, and thus is less dense and floats. Through a global conveyor belt of water, cold water starts at the the poles, cycles to the equator, where it is warmed, and then cycles back to the poles.
Answer:
The President of the United States is the head of the executive branch.
Explanation: