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Old World

The Old World is Europe, Asia, and Africa. The New World is the Americas. This distinction is an ethnocentric reflection of the European origin of our modern sciences.

Olfactory

the sense of smell. With the exception of prosimians, primates are relatively poor at olfactory sensing.

Omnivorous

the ability to live by eating both meat and vegetable foods. See carnivorous and herbivorous.

Order

a Linnaean classification category above the level of species and genus. Each order can consist of many species and genera.