Answer:
(D). water.
Step-by-step explanation:
Water makes up majority of all cells and is the most abundant molecule present in a cell along with other major biomolecules. It accounts for about 70% of total cell mass.
Water is necessary for the cells to perform most of their chemical reactions as it acts as a solvent and helps in transport of dissolved compounds from or into the cells.
Thus, the correct answer is option (D).