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