Which of these events during the age of exploration was a cause of the other three? a) warfare increased as european nations competed for land and power b) advances in learning and technology made long ocean voyages possible c) europeans brought food, animals, and ideas from one continent to another d) european diseases had an adverse effect on the native populations of new territories

B) advances in learning and technology made long ocean voyages possible.

Due to advances during the Age of Exploration (roughly 15th-17th century), long ocean voyages became possible. This launched an interest in exploration by sea of far away lands, particularly by Europeans. The desire to be the dominant sea power led to more competition for land and power, which in turn led to more warfare. However, as voyages were completed and trade established, Europeans brought food, animals and ideas from different places, in particularly America. This had an adverse effect on the native populations due to the diseases that Europeans carried, for which Americans had no immunity.

i think it was   tsar alexander ii