What term describes the hydrophobic tail of phospholipids?

The term that best describes the hydrophobic tail of phospholipids is "hydrophobic." Phospholipids are fundamental components of cell membranes, and they consist of two distinct parts: a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails.

The hydrophobic tails are made up of long hydrocarbon chains that do not interact favorably with water. Instead, they tend to aggregate together to minimize their exposure to aqueous environments. This characteristic is critical in forming the lipid bilayer of cell membranes, as it allows membranes to maintain their structure while providing a barrier to the passage of water-soluble substances.

In contrast, "amphipathic" would encompass both parts of the phospholipid molecule collectively, as it describes molecules that have both hydrophobic and hydrophilic regions. "Hydrophilic" refers specifically to the water-attracting head, while "polar" relates to molecules with regions that have an unequal distribution of electron density, which typically applies to the hydrophilic head of phospholipids. Therefore, "hydrophobic" is the most accurate term when specifically identifying the characteristic of the tails.