Routine inhalation by athletes in any city of ground-level particulates, ozone, and other gases such as nitrogen dioxide restricts the airways and can tax the ....... and cardiovascular systems

• Respiratory

• Impaction

• Asbestos

• Etymology

In the lower passages, particles end up in the bronchial region by way of ........ as particles lose their buoyancy.

• Encompass

• Sedimentation

• Diffuse

• Penetrate

Some manufacturers are already offering to r..... old models with catalytic converters.

Internal combustion engines in vehicles produce exhaust emissions that result in environmental ...........

• retrofit

• avenue

• degradation

• stationary

Switching to an all-electric engine vehicle that is powered by renewable resources obviates the need for fossil fuels and a ......... fuel-related products and processes that tax the environment

• compression

• plethora

• cultivate

• combustion

The most common internal combustion engine in automobile is the four-stroke engine, which completes a four-part cycle of intake, ........, combustion, and exhaust.

• compression

• stationary

• degradation

• allocation

The ........ engine does not run at all in such circumstances.

• impaction

• fire

• combustion

• diffuse

deeper in the lungs, particles d.... and latch onto lung walls in a random motion similar to that of gas molecules

This is an especially ....... problem in developing nations because of the prevalence of older, poorly maintained vehicles.

• plethora

• combustion

• impress

• pressing

................. in vehicles consume petroleum and other liquids such as gasoline.

• internal combustion engine

• hybrid electric vehicle

• automotive

• compression