Its not dictator its monarch
Option C. Columbus underwent deep voyages and discovered the present day America. He also discovered the marine route which associated the old Eastern world to the new Western world.
After the establishment of Sea route there was exchange of goods with other countries started. But the negative impact was that people of Eurasia were not healthy with high levels of immunity.
The interchange of food supplies also initiated the arrival of dangerous diseases too and major part of the European, native American and Asian population died causing shortage of human labor, this gradually lead to the slavery of Africans.
Two inventions from the World War two are the radar and the sonar, both of which had a huge impact in the war, but also after it, becoming a widely used devices all over the world.
The radar was an invention that was enabling detection of objects in the air. Initially it is was used for detection of planes, as that's where the biggest threat was coming. This device enabled the soldiers and the civilians to be warned about the oncoming danger, but also to be able to respond adequately to the threat.
The sonar was another invention inspired by the war. It had the same basic purpose as the radar, just that it was used for detecting objects in the water. This was a crucial instrument that gave the submarines big advantage in locating the enemy and destroying it, or if not capable of that, being able to move away and avoid it.
Answer:
Rail is a reliable shipping method on land and it's environmentally-friendly. You can ship machinery or even perishable goods by rail because it's fast and efficient. There are schedules and reliable delivery times, so you'll know when your goods are expected to arrive at their destination.
