Which element is known to be the most abundant on Earth?

The most abundant element on Earth is oxygen. This is primarily because a significant portion of the Earth's crust, as well as its atmosphere and water, is made up of oxygen-containing compounds. In the Earth's crust, oxygen forms various silicates and oxides, contributing to the high percentage of oxygen by mass.

Additionally, oxygen is crucial for life, participating in biological processes such as respiration and photosynthesis, which is why its presence is so significant both in the atmosphere and in living organisms.

While hydrogen is the most abundant element in the universe, its abundance on Earth is mainly found in compound forms, like water (H2O), rather than as a free element. Carbon and nitrogen are important elements for life as well, but they do not match the abundance of oxygen in terms of mass and presence in the Earth’s composition.