Which of the following best explains why air is considered a natural resource?
a. air is expensive to produce and keep clean.
b. air is a raw material for biological processes supplied by the earth.
c. air can be processed to generate expensive chemicals.
d. none of the above

France played a key role in the american revolutionary war (american war of independence; 1775–1783). motivated by the ideals of the new nation which were inspired by the french enlightenment, as well as its long-term rivalry with britain and so as to avenge their territorial losses during the french and indian war, france secretly began sending supplies to the americans in 1775.