What observation regarding family units confirms the genetic relationship between cinnamon bears and black bears?

Answer

A sow can give birth to a litter where one cub is black and another is cinnamon.

It is not uncommon for a sow of the species to give birth to a litter containing cubs of differing colors, such as one entirely black cub and another displaying the cinnamon coloring.

What observation regarding family units confirms the genetic relationship between cinnamon bears and black bears?
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