In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

[Q]: Why do birds possess gizzards?, Context: Like the reptiles, birds are primarily uricotelic, that is, their kidneys extract nitrogenous waste from their bloodstream and excrete it as uric acid instead of urea or ammonia through the ureters into the intestine. Birds do not have a urinary bladder or external urethral opening and (with exception of the ostrich) uric acid is excreted along with feces as a semisolid waste. However, birds such as hummingbirds can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. They also excrete creatine, rather than creatinine like mammals. This material, as well as the output of the intestines, emerges from the bird's cloaca. The cloaca is a multi-purpose opening: waste is expelled through it, most birds mate by joining cloaca, and females lay eggs from it. In addition, many species of birds regurgitate pellets. Males within Palaeognathae (with the exception of the kiwis), the Anseriformes (with the exception of screamers), and in rudimentary forms in Galliformes (but fully developed in Cracidae) possess a penis, which is never present in Neoaves. The length is thought to be related to sperm competition. When not copulating, it is hidden within the proctodeum compartment within the cloaca, just inside the vent. The digestive system of birds is unique, with a crop for storage and a gizzard that contains swallowed stones for grinding food to compensate for the lack of teeth. Most birds are highly adapted for rapid digestion to aid with flight. Some migratory birds have adapted to use protein from many parts of their bodies, including protein from the intestines, as additional energy during migration.
[A]: contains swallowed stones for grinding food to compensate for the lack of teeth


[Q]: Which land along with Prussia made up the Kingdom of Prussia?, Context: Although Brandenburg was a part of the Holy Roman Empire, the Prussian lands were not within the Holy Roman Empire and were with the administration by the Teutonic Order grandmasters under jurisdiction of the Emperor. In return for supporting Emperor Leopold I in the War of the Spanish Succession, Elector Frederick III was allowed to crown himself "King in Prussia" in 1701. The new kingdom ruled by the Hohenzollern dynasty became known as the Kingdom of Prussia. The designation "Kingdom of Prussia" was gradually applied to the various lands of Brandenburg-Prussia. To differentiate from the larger entity, the former Duchy of Prussia became known as Altpreußen ("Old Prussia"), the province of Prussia, or "East Prussia".
[A]: Brandenburg


[Q]: What did former mayor Greg Nickels propose for the population increase?, Context: In recent years, the city has experienced steady population growth, and has been faced with the issue of accommodating more residents. In 2006, after growing by 4,000 citizens per year for the previous 16 years, regional planners expected the population of Seattle to grow by 200,000 people by 2040. However, former mayor Greg Nickels supported plans that would increase the population by 60%, or 350,000 people, by 2040 and worked on ways to accommodate this growth while keeping Seattle's single-family housing zoning laws. The Seattle City Council later voted to relax height limits on buildings in the greater part of Downtown, partly with the aim to increase residential density in the city centre. As a sign of increasing inner-city growth, the downtown population crested to over 60,000 in 2009, up 77% since 1990.
[A]:
ways to accommodate this growth while keeping Seattle's single-family housing zoning laws


