Miners used canaries in mines to
a. detect wild animals.
b. detect dangerous gases.
c. look for paths through the earth.
d. lead the way through tunnels.

In a constitutional monarchy, the king or queen a. is a symbol of the nation b. runs for office c. controls the legislative branch d. has absolute control

Where was oil production at its highest in the 1980s and still remains important to the russian economy? central asia the ural mountains russian siberia the caucasus region

Which of these is a drawback of using natural gas? a. it is fairly safe for use in homes.b. it burns more cleanly than crude oil products.c. scientists have developed new ways of extracting it.d. during its extraction, groundwater can be contaminated.