Title: Old English.
Question: What Anglo-Saxon kingdom ruled parts of modern-day Scotland?

Title: Light-emitting diode.
Question: Shorter wavelength diodes provide wavelengths as low as what?

Title: Umayyad Caliphate.
Question: Traditionally, who did the Umayyads and Muhammad both descend from?

Title: Jehovah%27s Witnesses.
Question:
What do Jehovah's Witnesses maintain they want to protect?