The legend is that Newton discovered Gravity when he saw a falling apple while thinking about the forces of nature. Whatever really happened, Newton realized that some force must be acting on falling objects like apples because otherwise they would not start moving from rest.
The trolleys have been reduced over the last decades, after their initial increase as a public transportation, when new and better ways were discovered/produced for transport, their decline has started.
The buses since their invention, had grown in number and became a very important part of every city's public transportation, and still are.
The rapid transit is the most recent one of the mentioned in here. It's popularity has grown, number increased, and is very practical because it is not causing traffic mess. It is very important transport asset nowadays and makes lives of millions of people much easier.
Ir is the third opinion, 100km area
Geography is called the mother of all sciences due to its links and influences on a range of other scientific fields including biology, math, anthropology, geology, astronomy and chemistry
