Why was 1990 an important year regarding air quality

The United States took first steps to keep the air clean. Cost-effective ways to reduce pollution were emphasized. The United States created the environmental protection agency. Hope this helps

Explanation:

Why was 1990 an important year regarding air quality? ... The United States took first steps to keep the air clean. Cost-effective ways to reduce pollution were emphasized. The United States created the environmental protection agency

Explanation:

the answer is b: the religion they practice.

here's why:

there were many different native american tribes and those with similar characteristics formed a main tribe or nation. each had its own language, religion and customs.

during the middle ages bibles and most christian literature was written in latin i think that’s the answer you are looking for