Answer:
The seven hills' denizens began to interact, which began to bond the groups. The city of Rome, thus, came into being as these separate settlements acted as a group, draining the marshy valleys between them and turning them into markets (fora in Latin).
Explanation:
Maybe, depends what you looking for
The steam engine of Thomas Newcomen and James Watt used the same principle of creating a vacuum and using steam to drive the device. The difference is that in James Watt's version, he uses a separate condenser to allow for a much greater efficiency in terms of power. The main difference with a separate condenser is that with a separate condenser, the main device can remain hot at all times, thus increasing efficiency.
I believe it was guerrilla warfare.
