* Oxygen (O): The most abundant element in the Earth's crust, it's also a major component of water, the atmosphere (as a gas), and is essential for life.
* Silicon (Si): The second most abundant element in the Earth's crust, it's also found in some minerals in the hydrosphere and is present in small amounts in organisms.
* Aluminum (Al): Another abundant element in the Earth's crust, it's found in some minerals in the hydrosphere and in small amounts in organisms.
* Iron (Fe): Found in the Earth's core, it's also present in some minerals in the hydrosphere and is essential for life (found in red blood cells, for example).
* Calcium (Ca): A major component of the Earth's crust, it's also found in the hydrosphere, is important for the formation of bones and shells in organisms, and contributes to atmospheric gases.
* Sodium (Na): Found in the Earth's crust and in significant amounts in seawater, it's also present in smaller amounts in organisms.
* Potassium (K): Found in the Earth's crust, it's also present in seawater and is crucial for the functioning of organisms.
* Magnesium (Mg): Found in the Earth's crust, it's also present in seawater and is important for photosynthesis in plants.
* Hydrogen (H): A major component of water, it's also present in the atmosphere and is essential for life.
It's important to note that the abundance of these elements varies significantly between the four components. For example, oxygen is the most abundant element in the atmosphere, while silicon is the most abundant element in the lithosphere.
Additionally, trace amounts of other elements are present in all four components of Earth.
