Extract the answer to the question from the following context. Question: What crucial element to insect respiration lies between the neck and abdomen of the insect? Context: Insect respiration is accomplished without lungs. Instead, the insect respiratory system uses a system of internal tubes and sacs through which gases either diffuse or are actively pumped, delivering oxygen directly to tissues that need it via their trachea (element 8 in numbered diagram). Since oxygen is delivered directly, the circulatory system is not used to carry oxygen, and is therefore greatly reduced. The insect circulatory system has no veins or arteries, and instead consists of little more than a single, perforated dorsal tube which pulses peristaltically. Toward the thorax, the dorsal tube (element 14) divides into chambers and acts like the insect's heart. The opposite end of the dorsal tube is like the aorta of the insect circulating the hemolymph, arthropods' fluid analog of blood, inside the body cavity.:6165 Air is taken in through openings on the sides of the abdomen called spiracles.
----
Answer: the dorsal tube

Extract the answer to the question from the following context. Question: Which of the following nations was not communist: South Korea, North Korea or the Soviet Union? Context: Menzies came to power the year the Communist Party of Australia had led a coal strike to improve pit miners' working conditions. That same year Joseph Stalin's Soviet Union exploded its first atomic bomb, and Mao Zedong led the Communist Party of China to power in China; a year later came the invasion of South Korea by Communist North Korea. Anti-communism was a key political issue of the 1950s and 1960s. Menzies was firmly anti-Communist; he committed troops to the Korean War and attempted to ban the Communist Party of Australia in an unsuccessful referendum during the course of that war. The Labor Party split over concerns about the influence of the Communist Party over the Trade Union movement, leading to the foundation of the breakaway Democratic Labor Party whose preferences supported the Liberal and Country parties.
----
Answer: South Korea

Extract the answer to the question from the following context. Question: Why was it problematic to regulate the fan speed with a heat sensor? Context: Updated Motorola CPUs made a faster machine possible, and in 1987 Apple took advantage of the new Motorola technology and introduced the Macintosh II at $5500, powered by a 16 MHz Motorola 68020 processor. The primary improvement in the Macintosh II was Color QuickDraw in ROM, a color version of the graphics language which was the heart of the machine. Among the many innovations in Color QuickDraw were the ability to handle any display size, any color depth, and multiple monitors. The Macintosh II marked the start of a new direction for the Macintosh, as now for the first time it had an open architecture with several NuBus expansion slots, support for color graphics and external monitors, and a modular design similar to that of the IBM PC. It had an internal hard drive and a power supply with a fan, which was initially fairly loud. One third-party developer sold a device to regulate fan speed based on a heat sensor, but it voided the warranty. Later Macintosh computers had quieter power supplies and hard drives.
----
Answer:
it voided the warranty