What were the 5 events that helped "increase" in European exploration

Which of these statements best describes the ambiguity in this excerpt

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.

Is the weather changing? consider the data of severe weather that includes tornadoes occurring throughout the u. s. over the last four years. compare the severe weather for the last three years. then compare the first three months of 2017 with that data. based on previous years, what might the prediction be for weather during 2017?