In real-life, it’s common to ask or be asked questions that can be answered with “yes” or “no”. “Is an apple a fruit?” Yes. “Do you like asparagus?” No.
Now consider a similar statement that can be answered with a “true” or “false”: “Apples are a fruit”. It’s clearly true. Or how about, “I like asparagus”. Absolutely false (yuck!).
These kinds of sentences that have only two possible outcomes: yes/true, or no/false are so common, that many programming languages include a special type for dealing with them. That type is called a Boolean type (note: Boolean is properly capitalized in the English language because it’s named after its inventor, George Boole).
Boolean variables