Which of the following is NOT considered part of the hydrosphere?

The planet's crust is not considered part of the hydrosphere because the hydrosphere specifically refers to all water bodies and forms present on Earth, including water in oceans, lakes, rivers, and glaciers, as well as water vapor in the atmosphere and moisture found in the soil. The hydrosphere encompasses all different states of water, whether liquid, solid, or gas.

In contrast, the planet's crust refers to the outermost solid shell of Earth, composed of rocks and minerals. It is part of the lithosphere, which includes the rigid outer layer of the Earth, and does not encompass water or related components. Therefore, while the other options—water in lakes, water vapor in the atmosphere, and soil moisture—are all integral components of the hydrosphere, the planet’s crust remains separate from this classification.