Questions: 1. The world's largest producer of oil is: a) China b) United States c) Russia d) Saudi Arabia 2. The theory of peak oil: a) Correctly predicted the peaking of world oil production in 2005 b) Was proposed by Hubbert in the 1950's c) Predicts that oil production peaks every 30 years d) None of the above

The answer to the first question is (b) United States: the world's largest producer of oil.

Explanation for each option: a) China - Incorrect. While China is a significant producer of oil, it is not the largest. b) United States - Correct. The United States is currently the largest producer of oil, surpassing both Saudi Arabia and Russia in recent years. c) Russia - Incorrect. Russia is one of the top oil producers but not the largest. d) Saudi Arabia - Incorrect. Saudi Arabia is a major oil producer but has been surpassed by the United States.

The answer to the second question is (b) Was proposed by Hubbert in the 1950's.

Explanation for each option: a) Correctly predicted the peaking of world oil production in 2005 - Incorrect. The theory of peak oil did not specifically predict the peaking of world oil production in 2005. b) Was proposed by Hubbert in the 1950's - Correct. The theory of peak oil was indeed proposed by geologist M. King Hubbert in the 1950s. c) Predicts that oil production peaks every 30 years - Incorrect. The theory does not predict a regular 30-year cycle for oil production peaks. d) None of the above - Incorrect. Option (b) is correct, so this option is not applicable.

Summary:

1. The world's largest producer of oil is (b) United States.
2. The theory of peak oil (b) Was proposed by Hubbert in the 1950's.