what are the three essential chemical elements in the biosphere?

A) nitrogen, oxygen, and carbon
B) carbon, oxygen, and helium
C) oxygen, carbon, and iron
D) nitrogen, carbon, and hydrogen

Question

what are the three essential chemical elements in the biosphere?

A) nitrogen, oxygen, and carbon
B) carbon, oxygen, and helium
C) oxygen, carbon, and iron
D) nitrogen, carbon, and hydrogen

anonymous · Answer

@MSxSammiBooxX

anonymous · Answer

What do you think first off?

anonymous · Answer

i think A maybe ?
I'm PRETTY sure theres oxygen and i haven't heard about iron in the air and theres got to be carbon

anonymous · Answer

Yes I think it is A or D

Not sure exactly though

anonymous · Answer

I heard all four of those are essential chemical elements ;-;

anonymous · Answer

yeah they all sound familiar 
I'll go with A and tell you which ones right :)

anonymous · Answer

OK, thanks!

anonymous · Answer

IT'S A !!! THANK YOU 4 THE HELP :D

anonymous · Answer

Woohoo! No problem =)

anonymous · Answer

:)