Which colorless and odorless gas, produced by radioactive decay of uranium-238, is considered to be a form of pollution?

a. hydrogen
b. radon
c. oxygen
d. boron

Paraguay is one of the only two countries in the americas that don't have a coastal border. the country is slightly smaller than california. it was under a military dictatorship for 35 years, ending in 1989; today it is a constitutional republic. most of the population is roman catholic, and over 60% of the people live in cities. its environment is threatened by deforestation and water pollution. which of the following facts from the paragraph above best describes an element of paraguay's culture? (apex)