The U.S. currently makes up approximately what percent of the world’s total population?

Globally (at the current rate of deforestation) approximately what percent of tropical rainforest will be destroyed by 2050?

What Law of Physics states that when energy is converted from one form to another, some of it is always transformed to less usable or unusable energy?

What is the world’s human population projected to be in 2050?

If a parcel of air has a temperature of 15ºC and a specific humidity of 2g/kg, its capacity would be _____ and the relative humidity would be _____. 

Pollination and pest control are examples of ecologic services provided by living things.

What do we call a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically?

What common indoor air pollutant is responsible for tens of thousands of deaths from lung cancer each year in the U.S., being second only to cigarettes?

Which are currently used to generate most of the world’s electricity?

The air within an mP air mass is relatively _____ and _____.