Here's why:

* Water as a solvent: Water is an excellent solvent, allowing for the dissolving and transport of many important molecules and nutrients within the cell.

* Maintaining cell shape: Water helps maintain the cell's shape and structure.

* Chemical reactions: Water is a crucial component of many biochemical reactions that occur within the cytoplasm.

* Temperature regulation: Water's high specific heat capacity helps regulate the cell's temperature.

While water is the primary component, the cytoplasm also contains other substances, including:

* Proteins: Enzymes, structural components, and other functional molecules.

* Lipids: Fats and oils that make up cell membranes and other structures.

* Carbohydrates: Sugars and starches used for energy and cell signaling.

* Inorganic ions: Important for maintaining osmotic balance and cellular function.

However, water makes up the majority of the cytoplasm, creating a watery environment that facilitates all the vital functions of the cell.