The correct answer is b. an element
The explanation:
when the ELEMENT is define as substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means. Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen
Ex: diamond will be broken into carbon as well.
and SUBSTANCE: Material composed of only one kind of matter throughout (same atoms or same molecules).
What do u need help with?
2H2 + O2 = 2H2O since two elements created a compound, in this case water.
The answer is c it was 1510 is 1950 and in 1990 it was 16000
