Which two classification categories are used in binomial nomenclature

The most well-known living things have common names. For example, you are probably familiar with the small, red insects dotted with little black spots. You might call them 'ladybugs' or 'ladybird beetles.' But did you know there are actually many different species of these insects? Just using common names may make it difficult for scientists to differentiate between them, so every species is given a unique scientific name.

Binomial nomenclature is the formal naming system for living things that all scientists use. It gives every species a two-part scientific name. For example, a ladybug found in the United States goes by the fancy name of Harmonia axyridis.

The first part of a scientific name, like Harmonia, is called the genus. A genus is typically the name for a small group of closely related organisms. The second part of a scientific name, axyridis in this example, is the specific epithet. It is used to identify a particular species as separate from others belonging to the same genus. Together, the genus plus the specific epithet is the full scientific name for an organism.

I bet that you actually already know the scientific name for at least one animal, although you may not have realized it. Ever heard of the dinosaur T. rex? T. rex is actually a scientific name - the 'T' is just an abbreviation of the genus Tyrannosaurus. So the scientific name is actually Tyrannosaurus rex.

then that particular organisms become extinct.