Trade was what spread it the most. People were being in contact with other people and without knowing they spread the germs. The rats and fleas spread it too but that was spread through animals. The rats and the ticks would bite the people and they would be infected. Relatives would try to help them but without knowing they'd be sick too out of nowhere.
Answer: The concept of scale as used in human geography is a bit different than that used on a map. The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. For example, one inch on a map is equal to one mile on the ground.
Explanation:
Horizontal zones of vegetation found along hillsides that mainly result from vertical temp variations. These thermal belts are above freezing while areas above and below in air are below freezing.
Thermal belts refer to a mountainside zone where frost or freezing temperatures are less likely occur than they are higher or lower elevations.
I think it's the amoeba. They evolved 2.7 billion years ago.
