What are the characteristics that distinguish one type of organism from another?

The species is the smallest unit in the classification of living organisms. Within a species, organisms have identical characteristics (size, genes, color, etc.) and thus differ from other related species. This can be understood from the example of animals such as bears (part of the bear family). Polar bears are larger, their color is white, they live in the snow and swim in the sea, they are predators. They cannot be confused with another bear, the panda, which is smaller, lives in the forests and eats bamboo, and is black and white in color.