Environmental factors like sunlight, temperature and food supply.
Males and females have similar sexual characteristics with others of their gender.
Relatives share similarities in appearance due to their common genetic make up.
People with ancestors from the same regions of the world often share similar physical characteristics like skin, hair color, facial characteristics, body shape, and stature.
Exposure to ultraviolet rays (UV) can darken or tan a person’s skin.
Exposure to ultraviolet rays (UV) can alter genetic characteristics.
Varying UV causes no impact.
They represent cultural differences in our society.
They have been used to assign undisclosed information.
They have been used to enlighten people's awareness.
Pheomelanin, which is red to yellow in color and is produced by those with light complexions
Eumelanin, which is dark to black in color and is produced by those with dark-colored skin.
Melanin causes increased radioactivity.
People also differ in the number and size of their melanin particles.
Helps the eyes filter light.
Helps the body clean bacterial impurities.
Helps the body maintain healthy folic-acid levels.
Helps in converting oxygen to blood cells.
Helps the body absorb calcium.
Helps the body absorb phosphorus.
Helps in bone growth and repair.
Between dietary nutritional needs.
Between the evolutionary demands of photo-protection
Between the need to create vitamin D in the skin.
Between the evolutionary demands of hunter gatherers.