An island is a land surrounded by a body of water. For example, Hawaii is an island because it is surrounded by the Pacific Ocean.
Because the US is more popular and has warmer weather
Some of the negative effect of immigration are
1. Overcrowding ( could increase cost of housing)
2.increasing cost of services such as health care and education
3. Disagreement between different religions and cultures
4. It might stimulate capital formation and increase the level of *brain gain*.
5. Potential fall in real wages,especially for low skilled workers.
I hope this helps