Answer:
4 billion years
Explanation:
Scientists have found the oldest known rocks on Earth. They are 4.28 billion years old, making them 250 million years more ancient than any previously discovered rocks. Earth formed about 4.6 billion years ago from a disk of gas and dust circling the sun.
The answer is: [A]: troposphere .
___________________________________________________
Checks and balances keep one branch from overpowering the next.
ex: Executive Branch = Legislative, Legislative = Judicial, Executive = Judicial etc.
Answer:
D
To improve soil quality and conservation
