What is Net loss of oxygen?

Net loss of oxygen is when there’s more oxygen used up than oxygen added back in a place.

Imagine you're playing hide and seek in a big treehouse with your friends. Every time someone hides, they use a little bit of air (like oxygen) to breathe. But when they come out, they don’t always bring new air back with them, sometimes the air inside stays the same or even gets used up more.

Now think about the whole treehouse as a place where people are breathing in and out. If more people are hiding than coming out, the oxygen starts to run low because more is being used than added, making it harder for everyone to breathe, that’s like a net loss of oxygen.

In your body or even in the Earth's atmosphere, oxygen is always moving around. If you're doing something that uses up more oxygen than it adds, like exercising hard or burning fuel in a car, then there's a net loss of oxygen happening somewhere, just like when too many friends hide and don’t come out fast enough.