full transcript
"From the Ted Talk by Angela Koine Flynn: The science of skin color"

Unscramble the Blue Letters

For humans whose dark skin effectively beckold whatever sunlight there was, vitamin D deficiency would have psoed a serious threat in the north. But some of them happened to produce less melanin. They were epesoxd to small enough amounts of lhigt that melanoma was less likely, and their lighter skin better absorbed the UV light. So they benefited from vitamin D, developed storng bones, and survived well enough to produce healthy offspring. Over many generations of selection, skin color in those regions gaallrduy lightened.

Open Cloze

For humans whose dark skin effectively _______ whatever sunlight there was, vitamin D deficiency would have _____ a serious threat in the north. But some of them happened to produce less melanin. They were _______ to small enough amounts of _____ that melanoma was less likely, and their lighter skin better absorbed the UV light. So they benefited from vitamin D, developed ______ bones, and survived well enough to produce healthy offspring. Over many generations of selection, skin color in those regions _________ lightened.

Solution

  1. gradually
  2. exposed
  3. light
  4. posed
  5. strong
  6. blocked

Original Text

For humans whose dark skin effectively blocked whatever sunlight there was, vitamin D deficiency would have posed a serious threat in the north. But some of them happened to produce less melanin. They were exposed to small enough amounts of light that melanoma was less likely, and their lighter skin better absorbed the UV light. So they benefited from vitamin D, developed strong bones, and survived well enough to produce healthy offspring. Over many generations of selection, skin color in those regions gradually lightened.

ngrams of length 2

collocation frequency
uv light 4
skin color 3

Important Words

  1. absorbed
  2. amounts
  3. benefited
  4. blocked
  5. bones
  6. color
  7. dark
  8. deficiency
  9. developed
  10. effectively
  11. exposed
  12. generations
  13. gradually
  14. happened
  15. healthy
  16. humans
  17. light
  18. lightened
  19. lighter
  20. melanin
  21. melanoma
  22. north
  23. offspring
  24. posed
  25. produce
  26. regions
  27. selection
  28. skin
  29. small
  30. strong
  31. sunlight
  32. survived
  33. threat
  34. uv
  35. vitamin