Which of the following statements is true?

a. spf 10 is the minimum for safe protection from the sun.
b. from 10am to 4pm are the most dangerous hours for exposure to the sun.
c. we need vitamin d from the sun so there is no unsafe exposure level.
d. there is only one kind of harmful uv ray from the sun.

well when looking at this if you think about it   negativley and positivley   react with each other and when the first layer gets full they add layers it starts with 2 on the first layer and it constantly goes on until the official number is there

cutting out negative people, changing their diets, exercising, taking off days from work or school, etc

answersafety data sheets (sdss) and labels