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