Which issues led to the decline of the Roman Empire? Select all correct answers.

epidemics of foreign diseases

low taxes on Roman citizens

cruel and incompetent emperors

attacks from barbarian tribes

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.