Why does the body need vitamins and mineral ions?

What occupation did muhammad have before the first revelation

Compare the depth of field when focusing with low power and high power. which power has the greater depth of field?

Lola needs to sign 6 invitations. using stopwatch that measures time to tenths of a second, it takes lola 5.3 seconds to sign her full name. going by the accuracy of the stopwatch, which is the most accurate determination for the number of minutes lola needs to sign all 96 invitations