Elements heavier than hydrogen and helium constitute about ________ of the mass of the interstellar medium.
A. 0.002%
B. 2%
C. 70%
D. 98%
Answer:B
Elements heavier than hydrogen and helium constitute about ________ of the mass of the interstellar medium.
A. 0.002% B. 2% C. 70% D. 98%