They built a wall around the city to keep out invaders
Precambrian time, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, 541 million years ago. Precambrian time encompasses the Archean and Proterozoic eons, which are formal geologic intervals that lasted from 4 billion to about 541 million years ago, and the Hadean Eon, which is an informal interval spanning from 4.6 billion to 4 billion years ago. The Precambrian represents more than 80 percent of the total geologic record.
You have to find what the letter stands for in an equation
Federal government but i am not sure completely
Answer:
I think it's the presidential federal republic. but i'm not possitive
Explanation: