Cells are composed mainly of ________.
A) carbon, potassium, sodium, nitrogen
B) carbon, sodium, nitrogen, calcium
C) calcium, oxygen, sodium, potassium
D) carbon, hydrogen, nitrogen, oxygen
Answer: D
Cells are composed mainly of ________.
A) carbon, potassium, sodium, nitrogen
B) carbon, sodium, nitrogen, calcium
C) calcium, oxygen, sodium, potassium
D) carbon, hydrogen, nitrogen, oxygen