Simplify the Complex Fraction

question 174

Multiple Choice

Simplify the complex fraction.

---

Definitions:

Stratosphere

The layer of the Earth's atmosphere located above the troposphere and below the mesosphere, characterized by a slight temperature increase with altitude and the presence of the ozone layer.

Unhealthy Air

Air that is contaminated with pollutants at levels which are harmful to human health and the environment.

Urban Areas

Regions characterized by high human population density and vast human-built features in comparison to the areas surrounding them.

Ratio

A quantitative relationship between two numbers showing the number of times one value contains or is contained within the other.