How was Abu Bakr RA elected as the first caliph?

Describe the technology advancements that lead to explorers being able to sail great distances. [[ps: doesn't explain where. i am only speculating it's in europe.

Use the drop-down menu to complete the sentence. rome’s first civil war began as the result of conflict between

Which of the following had the most significant impact in supporting portugal's e fforts to control the indian ocean spice trade