Upper respiratory allergies and inflammation and swelling of the adenoids, the tissue at the back of the nose, can cause poor fluid drainage from the middle ear to the external ear and therefore cause a blockage in the Eustachian tube. Excess fluid can lead to middle ear congestion.
1 Black skin and Asian skin have thicker and more compact dermis than white skin. This is also why blacks and Asians have fewer facial wrinkles than whites. 2  Black skin has more casual lipids and more moisture in the stratum corneum than white skin.  Black skin has 50% lower ceramides than white or Hispanic skin.
The Cherokee say people did come across the land bridge in their histories. They call them, The Others. These were the people with black hair and high cheekbones. The Cherokee say they were good people and intermarried with them. Their genes are where the black hair and high cheekbones come from.