You observe a tissue that has cells of varying heights. at first glance, it appears that the tissue has multiple cell layers, but upon closer investigation, you see that all of the cells attach to the same basement membrane. what classification would you give to this epithelial tissue?

pseudostratified columnar epithelium

Explanation:

The key to distinguished between pseudostratified columnar epithelium and stratified columnar epithelium is that all of the cells attach to the same basement membrane. Pseudostratified creates the false impression of being a multi-layered tissue but it is in fact made up of only one cell layer. What creates this false impression is the different heights that cells have. This tissue can have cilia or microvilli. Can be found where secretion or mucus is needed.  

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme