What is one thing that is invisible, found all over the world, and is necessary for us to survive?
Air of course!
Air is an invisible gas that is made of different things. It mostly contains nitrogen (78%) and oxygen (21%). Oxygen makes our brains and bodies work. Scientists say that the more oxygen our bodies contain, the healthier we are. Breathing in plenty of fresh, clean, air full of oxygen is one of the most important things we can do for our health.
Fresh air is also necessary for the health of all living things. Every animal that lives on land needs oxygen just like people do. Think of how much oxygen a cheetah needs when it's running across the savannah! Animals that live under water like whales and dolphins also need air. They come to the surface of the water and inhale oxygen before going back under water to swim.