Look at the chemical equation:

2h2s + 3o2 → 2h2o + 2so2

how many atoms of hydrogen (h) are present on both sides of the equation?

a. 2

b. 3

c. 4

d. 6

4

Explanation:

4 atoms on each size since hydrogen exist as a molecule

C. 4

Explanation:

From the left hand(reaction) side of the equation hydrogen exist as a molecule in hydrogen sulfide(2H2S) . what this simply means it contain two atoms . Now multiplying the bold number in 2H2S  with 2 atoms of hydrogen which constitute a molecule .it will give 4 . On the left Side hydrogen atom(2H2) is 4.

On the right(product) side where Hydrogen appear in the water molecules(2H20), multiply 2 by 2 (2H2) you will get 4 also.

so Hydrogen atom is 4 on both side of the equation.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

i think it is true since you can test the answer and can use observations to complete it.