For a typical fair-skinned Caucasian individual, adequate vitamin D could be photosynthesized safely by spending 10 to 15 minutes in the noontime sun on a clear day with 50 percent of skin area exposed to the sun.
For a typical fair-skinned Caucasian individual, adequate vitamin D could be photosynthesized safely by spending 10 to 15 minutes in the noontime sun on a clear day with 50 percent of skin area exposed to the sun.
对一个典型的浅肤色白种人来说，在一个晴朗的日子里，在正午太阳下将50％皮肤暴露在阳光下进行10到15分钟的光合作用可以安全的获得足够的维生素D。