What popular operating system are the Mac OS X series based on?

More Questions:

Who is the inventor of the KonMari Method?

What fashion brand was co-founded by artist Beyonce?

What relative does a Russian call "babushka"?

What is the name of the winged horse of Greek mythology?

Stores around the town square of Oxford, Mississippi closed during what author's 1962 funeral?

What is the minimum number of sides required to create a Polygon?

What bird is referred to as "windhover" in some areas?

What flowers are known as "mums"?

Which acids make up gastric acid in the human stomach?

What word is the actual title of the 1979 hit typically called "The Pina Colada Song"?

Where does SpongeBob SquarePants work?

What disorder did Muhammad Ali develop after retiring from boxing?

In which city was Joan of Arc burnt to death?

What Italian patriot led the Redshirts?

What is the name of the base twenty numbering system?