I am not completely sure, but I think it might be B, Migration out of a stage 3 or 4 country is higher than migration to it.
The reason the Indo- European languages dominated the globe geographically today was that <span> 'B) European colonization around the world helped spread the languages.'</span>
Answer:
Protostars are difficult to observe because they are surrounded by cocoons of gas and dust.
I believe it's globular and open are the main types.