Photosynthesis. Because the plants give off oxygen as a waste product. Carbon dioxide then moves from the air into the leaves of plants through tiny openings in the plants leaves.
An element's atomic number shows the number of protons in its nucleus.
C
A has 2H 2O on the left and 4H 2O on the right
B has 4H 4O on the left and 4H 2O on the right
D has 2H 2O on the left and 2H 4O on the right
C has 2H 2O and 2H 2O so is balanced.
B) simplest ratio of elements
An empirical formula is the simplest ratio of a compound. For example, a compound like C4H8 would have an empirical formula of CH2.
