Why does earth have a moon?
There are many theories on why the Earth has a moon, but the most prevailing one is that the moon formed out of debris from a collision between ancient Earth and a Mars-sized body named Theia.
Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:

Why does earth have a moon?

### Response:

There are many theories on why the Earth has a moon, but the most prevailing one is that the moon formed out of debris from a collision between ancient Earth and a Mars-sized body named Theia.
