Answer:
Around the world the most significant restriction on access to potable water is money. While access to raw water sources, clean or otherwise, is important, the purification process itself is expensive. Once water has been rendered potable, it is important that it be delivered without reintroducing contamination.
Ethnic conflicts has been a contemporary concern
Answer:
From a state of endangerment, many languages become extinct. When the speakers of a language are exterminated as what happened to Tasmanians in the 19th century, several languages suddenly died. Another reason for the extinction is the pressure exerted on a community to incorporate with a more powerful or larger group.
Answer:
B.
I could wrong that because there many theory.
I choose B that because my feelings think B make any sense?