Concept:The part of the Earth's crust covered by oceans and seas is known as the hydrosphere, which includes all water bodies on the planet.
Explanation:The Earth's surface is divided into different spheres based on their composition.
The lithosphere is the solid crust, while the atmosphere is the layer of gases above it.
The biosphere refers to all living organisms.
The hydrosphere, however, is the total water present on Earth.
This water exists in oceans, seas, lakes, rivers, and even underground.
Since oceans and seas are large saltwater bodies that cover about 71% of the Earth's surface, the region of the crust they cover is specifically the hydrosphere.
Therefore, the correct option is the hydrosphere, not the biosphere, ionosphere, or stratosphere.
Answer:D. hydrosphere