What is both burrowing mammal and a unit of measurement used in chemistry?

Answer:  Mole

What digit does every MasterCard start with?

Answer:  Five (5)

Draculin, a glycoprotein that prevents blood from clotting, is found in the saliva of what animal?

Answer:  Vampire bat

What M-word is defined as a device that changes sound into an electrical current?

Answer:  Microphone