A type of rigid airship named after German Count von Zeppelin, popular in the early 20th century....
The mathematical concept and number representing the absence of quantity....
The branch of biology that studies the animal kingdom....
A chemical element essential for human health, used in alloys and as a dietary supplement....
Any disease or infection naturally transmissible from vertebrate animals to humans....
A postal code system used by the United States Postal Service....
A school of Mahayana Buddhism emphasizing meditation and direct experience over theoretical study....
A landlocked country in southern Africa known for Victoria Falls and ancient ruins....
A mosquito-borne virus causing mild illness in adults but serious birth defects in pregnant women....
The king of the Olympian gods in ancient Greek religion and mythology....