What sparked the downfall of the U. S. oil industry in the 1980s? A. increased spending
B. new discoveries of oil
C. the government
D. OPEC actions

D. OPEC actions

Explanation:

The downfall of the US oil industry in the 1980s was caused by a reduced demand for oil caused by the energy crises of the 70s and with this reduced demand, there became an oil glut, because the production was also increased.

Therefore, this downfall of the oil industry in America in the 1980s was caused by increase in oil prices by OPEC (Organisation of Petroleum Exporting Countries).

a. theta waves. this is because the person is in a light sleep which means the brain waves would show these kind of waves.