The answer is Fraternal twins. This twins usually don't look like exactly the same because they don't share the same genetic material, they can't be distinguished as twins. This type of twins grow and born together in the womb from a unique fertilized egg.
Answer:
Individuals migrate because they think that they can improve their own lives or those of their families by doing so. Economic migration is triggered by the knowledge (or belief) that better economic opportunities exist in some other place.
I believe the answer is general environment.
Both of them essentially meant all the factors and conditions that affect economic situation in a nation as a whole.
This usually include things such as the legal policies that made by the government, The inflation rate that experienced, Resource availability, etc
