When is ozone considered a pollutant?
a. in the stratosphere
b. in the mesosphere
c. in the troposphere
d. in the thermosphere

What major factors play a role in global warming? 1. human activity and normal climate conditions 2. natural factors and human activity 3. normal climate conditions and abnormal human activities 4. abnormal human activities and natural factors

5. there were nearly 1,000 pirate attacks between 1994 and 2005 off the coast of according to the international maritime bureau's annual piracy report for 2005.

Acivilization exists for several hundred yeaars, developing its own language. such a civilization probably has been: a. farming corn b. suffering from a lack of contact with the outside world. c. isolated by mountains or some other physical barriers. d. starving from lack of trade.