Which of the following types of epithelium consists of a single layer of cells of varying heights?

The type of epithelium that consists of a single layer of cells of varying heights is called pseudostratified epithelium.

Explanation

1. Structure: Pseudostratified epithelium appears to have multiple layers due to the varying heights of the cells, but it is actually a single layer. Each cell touches the basement membrane, although not all reach the surface.

2. Function: This type of epithelium is typically involved in secretion and movement of mucus, primarily found in the respiratory tract, where it helps trap and transport particles out of the airways.

3. Characteristics: Pseudostratified epithelium often contains cilia and goblet cells, which produce mucus. The cilia help in the movement of mucus and foreign particles out of the respiratory system.

In summary, pseudostratified epithelium is characterized by its single-layer structure with varying cell heights, contributing to its specialized functions in secretion and protection within certain organs.