Which element plays the most dominant role in the composition of the Earth's oceans?
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon
The most dominant element in the composition of Earth's oceans is C. Hydrogen.
In order to determine this, we need to understand the composition of water, which is the primary component of Earth's oceans. Water (H2O) consists of two hydrogen atoms bonded to one oxygen atom.
Oxygen (O) is present in water, but hydrogen (H) is the element that has a more significant role. It is because there are two hydrogen atoms for every oxygen atom in a water molecule.
Therefore, the correct answer is C. Hydrogen.