Here's why:

* Simple refers to a single layer of cells.

* Columnar describes the shape of the cells, which are tall and narrow, resembling columns.

Simple columnar epithelium is found in areas where absorption and secretion are important, such as:

* The lining of the stomach and intestines

* The lining of the gallbladder

* Some parts of the respiratory tract

It's important to note that other types of tissues can also have elongated cells. For example, some types of muscle tissue are composed of elongated cells. However, the term "single layer of elongated cells" is most commonly used to describe simple columnar epithelium.