There are countless mixtures in the world. A mixture is a combination of two or more substances that are not chemically bonded together. This means that the components of a mixture can be easily separated by physical means, such as filtration or distillation.

Some examples of mixtures include:

* Air, which is a mixture of nitrogen, oxygen, and other gases

* Salt water, which is a mixture of water and salt

* Concrete, which is a mixture of cement, sand, and gravel

The number of possible mixtures is infinite, as there are an infinite number of substances that can be combined in different proportions.