To what extent did feudalism impact trans-regional trade in Western Europe between 600CE - 1200CE?

An education expert is researching teaching methods and wishes to interview teachers from a particular school district. she randomly selects ten schools from the district and interviews all of the teachers at the selected schools. which type of sample did she use in this study? a)systematic sample b)probability sample c)stratified sample d)cluster sample

This excerpt supports the idea that the sky chief valued

Which nims command and coordination structures are offsite locations where staff from multiple agencies come together?