BOOST LEVEL 41 (2) NITROGEN & ADS- PART 1 - LISTENING

Earth's atmosphere is made up of approximately ___% nitrogen.

• 0.72
• 0.78
• 0.8
• 0.85

Oxygen makes up about ___% of Earth's air.

• 0.19
• 0.21
• 0.23
• 0.25

Argon, which is ___% of our air, is formed from the decay of potassium.

• 0.009
• 0.0093
• 0.0095
• 0.0098

The remaining ___% of the air contains various particles and trace gases.

• 0.0005
• 0.0007
• 0.0009
• 0.001

___% of every breath we take likely contains man-made pollutants.

• 0.0005
• 0.0007
• 0.0009
• 0.001

Primary pollutants are directly emitted from a source, such as ___ or dung.

• wood
• coal
• plastic
• metal

Pollutants can transform into more toxic secondary pollutants due to ___.

• radiation
• oxidants
• heat
• pressure

Sulfur oxides released from burning coal can oxidize to form ___.

• ozone
• methane
• sulfates
• carbon dioxide

Exhaust from vehicles releases nitrogen oxides and hydrocarbons which can form ___.

• carbon dioxide
• ozone
• methane
• hydrogen

Most cars produced since the ___'s have catalytic converters to reduce certain emissions.

• 1970
• 1980
• 1990
• 2000