Why did early Portuguese explorers and traders not have a lasting impact on the interior of Africa? Use evidence from the text to support your answer.

What is the "great pacific garbage patch"? (a) a large area of marine debris concentrated by rotating ocean currents (b) a large area around the pacific rim where debris collects from natural disasters such as tsunamis (c) an area in the pacific ocean where trash is intentionally dumped due to lack of landfill availability (d) a large trash dump located in hawaii

All of the following came out of china and were exchanged along the silk road, except a. papermaking b. block printing c. buddhism d. compasses select the best answer from the choices provided a b c d

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks