Approximately what percentage of milk is water?

Milk is composed primarily of water, making it one of the main constituents by weight. The correct percentage of water in milk is about 86%. This high water content is significant because it affects the nutritional properties of milk, its viscosity, and its behaviors during processing and storage.

The other options do not accurately reflect the composition of milk. While it is true that milk contains a substantial amount of water, the percentages given in the other choices either understate or overstate this crucial component. 75% and 80% are lower than the actual percentage, which means they do not accurately depict how much of milk's makeup consists of water. On the other hand, 90% is an overestimate, as it suggests an unrealistically high water content that does not align with standard milk composition data. Thus, recognizing that water constitutes approximately 86% of milk is essential for understanding its overall properties and characteristics.