Junction which facilitates the exchange of small and sometimes big molecules is $:-$

Simple columnar epithelium is composed of a single layer of __ $(A)$ __ cells. Whose nuclei are located at the __ $(B)$ __ . Choose the correct option $:-$

Inner lining of gut,stomach and liver is composed of

$A$ student was given a sample of tissue. He observes and concludes the following characters.
$(i)$ The cells are composed of a single layer of tall and slender cells.
$(ii)$ Their nuclei are located at the base.
$(iii)$ Free surface may have microvilli.
$(iv)$ It is found in the lining of stomach and intestine.
$(v)$ They help in secretion and absorption. Based on the above features identify the epithelium.

Describe the types and functions of Glandular epithelium.

Which insoluble protein is present in scales?