What percentage of living things is made up of water?

The correct answer, which indicates that approximately 70% of living organisms are comprised of water, highlights the fundamental role of water in biological processes. Water serves as a critical solvent in which many biochemical reactions occur, facilitating the transport of nutrients and waste products within cells and throughout the body. This high percentage reflects water's essential contributions to the structure of cells, regulation of temperature, and maintenance of homeostasis. The abundance of water in living systems varies among different organisms, but the general estimate of around 70% underscores its universal importance across various forms of life.

Considering this context, the other percentages suggest either a misunderstanding or oversimplification of water's role in biology, as they do not accurately represent the average composition of living organisms.