Why are the pyramids considered one of ancient Egypt's greatest achievements?

Pyramids are considered to be one of Egypt's greatest accomplishments, since it took both skills and techniques to build them. It took nearly 100,000 men in 20 years to construct the pyramids. They were the largest structures ever built, and it took massive quantities of supplies and labor to do them.

c is the answer for this

first, the romans stayed isolated because they had to defend their own territories from neighboring cities that were harassing them, like the etruscans. second, once the romans managed to defeat their neighbors, and started to expand their territory, they started to build roads and bridges. finally, now that the romans have covered their territory with roads functioning as highways, they could mobilize their legions faster to assemble larger military units in a specific place