Which statement best explains how the idea of Manifest Destiny mentioned in Source 1 contributed to the Mexican-American War?
A The United States wanted to limit the spread of slavery.
B The United States wanted to recover from an economic depression.
C The United States wanted to adopt cultural ideas from other countries.
D The United States wanted to take over the territories of other countries.

Which suggests the most critical aspect of the peak oil theory? 1) controversy rages over rumors that the fracking lobby in washington has influenced the statistics. 2) supporters and critics argue endlessly over the rate of extraction and shape of the bell curve. 3) saudi arabia will soon have to begin fracking, leading to protests and further destabilization. 4) a new oil discovery means a fresh peak cycle, making that region the target of aggressors.