there are six elements that make up most of the human body. Which of the following is not one of these six elements?

oxygen, carbon, hydrogen,

Explanation:

hope this helped u :)

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."