While many sudoku boards only have the rule that each digit (1-9) can only appear once per row, column, and 3x3 grid, more advanced boards are only solvable if similar digits are also not within the distance of one move by this chess piece.
Knight
This deciduous tree in the quassia family is a problem because it quickly forms dense thickets that outcompete native plants. It's also the primary host for spotted lanternflies.
Tree of heaven (Ailanthus altissima)
Magpies, jackdaws, and scrub jays are all lower classifications of what family of birds?
Corvids
It's a percussive instrument where a hollow gourd (often fish- or frog-shaped) is rubbed with a stick along parallel notches to create a ratchet or zipper sound.
Güiro
Si atraviesas el peligro y no mueres, has hecho esto.
pervivir / sobrevivir (to survive, to endure)
The 2010 Hadestown concept album by Anaïs Mitchell lists 29 personnel members, including everyone from the vocalists to trombonists to engineers. Tanya Kalmanovitch is listed as the only musician to play what instrument, which never made it to the stage musical's orchestra? You can't spell "Olivia" without it!
Viola
Likely introduced to the Northeast from packing materials shipped from Asia, this insect and its larvae which eat inner tree barks have been responsible for the deaths of hundreds of millions of trees over the last 25 years.
Emerald ash borer (Agrilus planipennis)
Some birds produce a pale, yellow, cottage cheese-like substance called crop milk to regurgitate to their young. This trait in flamingoes and emperor penguins may suggest convergent evolution, but it is best known for being produced by every type of this stereotypically dumb bird.
Pigeon/dove
The buccin (or buccin à tête de ___) is a visually distinctive trombone used in 19th c. France, which features a bell in the shape of this creature's head and open jaw.
Serpent/dragon
"¡Estaba nabando en la playa y me picó una de estas!" También se le llama una medusa.
Aguaviva (jellyfish)
Should we go to Lux?
No
Touching this massive, noxious plant in the Adirondacks could make you suspect you've contracted vampirism, as people are encouraged to avoid direct sunlight for 48 hours after contact or risk severe pain, large blisters, dark scarring, and long-term sun sensitivity, but it's actually just phytophotodermatitis.
Giant hogweed (Heracleum mantegazzianum)
Much like amphibians, reptiles, and most fish, birds feature just one orifice for urinary, digestive, and reproductive tracts, called this. (For an additional point, name either of the only two mammals, or their shared order, which also feature this opening.)
Cloaca (Monotremes: platypus, echidna)
This small Mesoamerican vessel flute features four to 12 holes and comes in various shapes, such as an egg (as seen in its titular Legend of Zelda game) or a variety of birds (fitting for its name, meaning "little goose"), both of which are less ergonomic than ones of a typical transverse shape.
Ocarina
Similar a una cosa o un hogar, es un lugar donde una familia come y duerme, y trabaja tal vez.
Vivienda (dwelling, housing, residence)
Rochester, NY falls around 6b on maps developed by the USDA, which use data on the country’s average annual minimum temperature to divide the US into geographic areas, called these, which affects which plants can grow where.
Hardiness zones
Walking through poison ivy can leave you with an itchy rash spread by this oil that coats the plant, which is why hikers are encouraged to wash any skin, gear, and clothing that may have touched it to prevent spreading.
Urushiol
Whether a southern mask-weaver is building a nest in a tree or a cattle egret is perched atop a water buffalo's back waiting to spot earthworms under the soil it kicks up, many birds form symbiosis with another species which is neither harmed nor benefitted, called this.
Commensalism
As early as 1602, writings of a hypothetical remedy for daydreaming appeared throughout Europe. Patients would sit and listen to the 16 animals arranged by natural pitch and whose tails replaced the instrument's strings, which gave it the name Katzenklavier, or this in English.
Cat piano
Una persona que practica habilidades esenciales al aire libre como deporte o pasatiempo.
Supervivencialista (survivalist)
The oldest known use of acanthus motifs in architecture appears on the Corinthian columns of the Temple Epicurius at Bassae in Arcadia, a 450 BCE dedication to this Greek deity.
Apollo
One of the most successful non-native plants to invade forest understories, this biennial herb from Europe is identifiable by basal rosette leaves; clustered white flowers; and thin, curving fruit pods. It also emits a strong odor akin to the allium from which it earns part of its name.
Garlic mustard (Alliaria petiolata)
While many species evolved to have hollow bones to reduce weight, one in particular did the opposite: evolving denser bones and smaller wings to become more efficient at diving. While they can dive 25-150 feet deep, flight comes with having the highest energy cost of any bird for this species, also called the "sea crow" or "sea raven."
Cormorant
The Delacorte Clock in Central Park features a menagerie of an accordion-playing elephant, tambourine bear, flute goat, horn kangaroo and joey, violin hippo, and drum penguin which rotate every half hour, as well as a bell that is struck by two of these animals wielding mallets.
Monkeys
Se puede encontrar en la mayoría de los parques de los atracciones, pero su nombre en México—"los caballitos"—es más divertido que este nombre se utiliza en España.
Tiovivo (carousel)