Question 1
Ninety-two elements occur naturally. How many of them are found inside living bodies?
The right answer is the one marked above.
Roughly 25 of the 92 naturally occurring elements turn up in living bodies, in different forms and in different places.
Four is the count of the elements that do most of the building — carbon, hydrogen, oxygen and nitrogen — but a living body needs a good many more than four to keep working.