Agene whose expression can be easily visualized and monitored is called a

The expression of a reporter gene can be easily visualized and monitored.

Explanation:

The reporter gene is a type of gene which is attached to a regulatory sequence of an another gene in a cell culture, bacteria, plants or animals. A reporter gene is generally used as an indicator, that is used to determine that a certain gene has been taken up or expressed in a cell or population of an organism.