Here's why:

* Unicellular: Goblet cells are individual cells, unlike multicellular glands which are composed of many cells.

* Gland Cell: Their primary function is to secrete substances. In the case of goblet cells, they secrete mucus, which is a sticky, protective substance.

Goblet cells are commonly found in epithelial tissues lining the digestive and respiratory tracts, where their mucus production plays a crucial role in lubrication, protection, and trapping foreign particles.