That's a great question! What surrounds us is often called the environment. Here's a breakdown of what makes up our environment:

* Living things: This includes all plants and animals, from tiny microbes to giant trees and whales.

* Non-living things: This includes things like air, water, soil, rocks, and sunlight.

Let's break down the things you mentioned:

* Air: The invisible gas that surrounds us, made up of mostly nitrogen and oxygen. We need air to breathe.

* Water: The liquid that covers much of our planet and is essential for life. We drink water, use it to grow food, and it's important for all living things.

* Land: The solid ground we stand on, made up of rocks, soil, and mountains.

* Trees: Large plants that provide us with oxygen, shade, and wood. They are also home to many animals.

Together, all these elements create a complex and interconnected system that supports life on Earth.