Hydrogen gas, oxygen gas and water
4H2O (l) ---> 2H2O (l) + O2 (g) + 2H2 (g)
An index fossil is a fossil that is useful for dating and correlating the strata in which it is found.
Or it is a fossil that helps you find the date where it has been found. I rephrased that.
Answer:
78
Explanation:
atomic number is number of protons
The options are labelled as:
1 2
3 4
5 6
7 8
Protons: 1, 5, 7
Neutrons: 2, 8
Electron: 3, 4, 6