This is a bit of a trick question! Earth exists as a planet, but it's made up of many elements. It's impossible for Earth to exist without all of the elements that make it up, including:

* Oxygen: The most abundant element in the Earth's crust.

* Silicon: Another major component of rocks.

* Iron: Found in the Earth's core and responsible for its magnetic field.

* Aluminum: Found in many rocks and minerals.

* Calcium: Important for building bones, teeth, and shells.

* Sodium: Found in the ocean and essential for many biological processes.

* Potassium: Essential for plant growth and nerve function.

* Magnesium: Important for chlorophyll production.

* And many more...

So, there's no one element that Earth can exist without. It's a complex planet made up of many different elements working together.