What has created this fault line?

Women should not drink alcohol when they are pregnant because ethyl alcohol is a type of – 

Which infectious disease is the leading cause of death in the world?

The National Wildlife Refuge System has more than 500 refuges. Most of these refuges protect – 

Old-growth forests are forests that have remained uncut and undisturbed by man or natural disasters for _________ years or more.

Which of the following is NOT a part of climate change?

A layer of ozone in our atmosphere is crucial to our survival for two reasons. What are they?

What is this structure called? What is the purpose of this structure?   

What is the number one cause of species extinction?

Match the major outdoor pollutant with its description.