Two mountain ranges, the Alps and the Apennines, helped to protect Rome from invasion. The apennines split the Italian peninsula in half so whenever someone tryed to attack they could counter attack anytime. Any army attempting to attack Rome would be at risk of attack from the other side of the mountains. The Alps hepls rome from invaders because of the slow narow paths which will give them time to know invaders are coming.
The metetoranian sea provided water to many civilizations along the east cost of egypt. This along with the red sea protected the people of eygpt. Also my water falls provided water an protection for them. What helped most was all of the deserts east and west. The Sahara desert is the largest desert in the world and that gave them a huge advantge because they where very protected my water and the desert. Also the Sahara was very hard to walk and manover in so they had the uper hand if anyone tryed to attak there civilization.
Rich volcanic soil makes the Tiber river valleys ment for agriculture. The Roman population grew quickly, thanks to growing production of grains, olives and other crops. The extra population later helped Romen's military growth by providing a large supply of troops. Also the growth in food helped Rome to establish trade ties with other Mediterranean powers.