Q: Extract the answer to the question from the following context. Question: A pack of cards is also called a? Context: Melbourne's CBD, compared with other Australian cities, has comparatively unrestricted height limits and as a result of waves of post-war development contains five of the six tallest buildings in Australia, the tallest of which is the Eureka Tower, situated in Southbank. It has an observation deck near the top from where you can see above all of Melbourne's structures. The Rialto tower, the city's second tallest, remains the tallest building in the old CBD; its observation deck for visitors has recently closed.
A: deck

Q: Extract the answer to the question from the following context. Question: The second half of the term antigen comes from what word? Context: The humoral (antibody) response is defined as the interaction between antibodies and antigens. Antibodies are specific proteins released from a certain class of immune cells known as B lymphocytes, while antigens are defined as anything that elicits the generation of antibodies ("anti"body "gen"erators). Immunology rests on an understanding of the properties of these two biological entities and the cellular response to both.
A: "gen"erators

Q: Extract the answer to the question from the following context. Question: Who later operated a slave trade in this region? Context: Guinea-Bissau was once part of the kingdom of Gabu, part of the Mali Empire; parts of this kingdom persisted until the 18th century. Other parts of the territory in the current country were considered by the Portuguese as part of their empire. Portuguese Guinea was known as the Slave Coast, as it was a major area for the exportation of African slaves by Europeans to the western hemisphere. Previously slaves had been traded by Arabs north to the northern part of Africa and into the Middle East.
A: Europeans

Q: Extract the answer to the question from the following context. Question: What type of capacitor prevents this problem? Context: The third-generation iPod had a weak bass response, as shown in audio tests. The combination of the undersized DC-blocking capacitors and the typical low-impedance of most consumer headphones form a high-pass filter, which attenuates the low-frequency bass output. Similar capacitors were used in the fourth-generation iPods. The problem is reduced when using high-impedance headphones and is completely masked when driving high-impedance (line level) loads, such as an external headphone amplifier. The first-generation iPod Shuffle uses a dual-transistor output stage, rather than a single capacitor-coupled output, and does not exhibit reduced bass response for any load.
A:
dual-transistor output stage