Which peoples attecked the byzantine empire? what parts of the empire did they invade?

What kind os source would a historian use to get a firsthand account of a past event

Which statement tells an advantage george washington had in his first term as the first president of the united states?

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.