What is the religion of Saudi Arabia?

Saudi Arabia has how many migrants within its borders?

Where is the Persian Gulf?

Which of the following power sources provides
the highest percentage of global energy?

Which is the cleanest of the fossil fuels?

Particulate matter (PM) comes mainly from _______________.

The Parthenon is in _________.

Acid rain leaches nutrients from _________.

The pH of normal rain is ____.