Explain what a boolean variable is in programming.

A boolean variable is a data type that can only take two values: True or False. It is used to store the results of logical expressions and conditions, for example, to check whether a certain condition is met.

Example in Python:

is_active = True
is_logged_in = False

if is_active and is_logged_in:
    print("User is active and logged in")
else:
    print("Access denied")