How did people living at higher latitudes benefit from lighter-colored skin?
A. With less total UV light, lighter-colored skin allows more production of vitamin D.
B. With less total UV light, lighter-colored skin protects vitamin D from degradation.
C. With less total UV light, lighter-colored skin provides protection against skin cancer.
D. With less total UV light, lighter-colored skin keeps people warmer.
E. With less total UV light, lighter-colored skin was important for social interactions.
Ans: A. With less total UV light, lighter-colored skin allows more production of vitamin D.
You might also like to view...
Two-thirds of the available freshwater is
a. used as drinking water for animals. b. used as drinking water for humans. c. used for irrigation. d. wasted.
A penguin's feet are nearly as cold as ice, while the bird's core body temperature is much higher. Which of the following explains this observation?
A. countercurrent heat exchange between warm blood in arteries and cold blood in veins B. countercurrent heat exchange between warm blood in veins and cold blood in arteries C. blood supply to legs shut off by vasoconstriction D. no muscles in the feet of penguins to generate heat E. heat cannot diffuse from body core to feet because feet are too far away
Which is false about estrogen receptors in humans?
a. They are restricted to females. b. They are necessary for sperm maturation. c. They bind the insecticides kepone and DDT, now banned in the U.S. d. Endocrine disruptors affecting them may be responsible for declining sperm counts in western countries. e. All of these are false.
________ is a syndrome that occurs in females who have only a single X chromosome (XO)
Fill in the blank(s) with correct word