World News for Students of English

29-07-2026 07:00

Human skin tones vary globally due to our long evolutionary relationship with ultraviolet (UV) radiation. Near the equator, high UV levels led to dark pigmentation with abundant melanin, which protects DNA from solar damage.

However, as human ancestors migrated to regions with significantly lower UV levels, high melanin became a health disadvantage. Some UV wavelengths are essential for synthesizing vitamin D, a key nutrient required for strong bones and a healthy immune system. To ensure survival in low-UV environments, human skin adapted by becoming lighter. Additionally, people with moderate skin tones developed the ability to tan by producing melanin during sunnier summer months and losing it in winter.

Today, because people migrate rapidly across different regions, many must consciously manage their relationship with the sun through lifestyle choices, including using skin protection or taking vitamin D supplements.

Difficult words: abundant (more than enough), synthesize (to produce a substance in the body through a natural biological process), consciously (aware of what you are doing and doing it on purpose).

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