Q81. Which is the hardest synthetic substance in the world?
a) Wurtzite boron nitride
b) Cubic boron nitride
c) Silicon carbide
d) Titanium carbide
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Correct Answer: a) Wurtzite boron nitride
Explanation: Wurtzite boron nitride is the hardest synthetic substance in the world. It is a crystalline compound made up of boron and nitrogen atoms and has a similar structure to diamond. Wurtzite boron nitride is used in various applications, including cutting tools, abrasives, and protective coatings.
Q82. Which is the hardest substance found in meteorites?
a) Lonsdaleite
b) Graphite
c) Iron-nickel alloy
d) Olivine
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Correct Answer: a) Lonsdaleite
Explanation: Lonsdaleite, also known as hexagonal diamond, is the hardest substance found in meteorites. It is a rare, naturally occurring mineral that forms when graphite-containing meteorites impact the Earth’s surface at high velocities. Lonsdaleite is structurally similar to diamond but has a hexagonal crystal lattice.
Q83. Which is the hardest natural substance found on Earth?
a) Diamond
b) Graphite
c) Quartz
d) Corundum
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Correct Answer: a) Diamond
Explanation: Diamond is the hardest natural substance found on Earth. It is a crystalline form of carbon and has a unique combination of properties, including extreme hardness, high thermal conductivity, and chemical inertness. Diamonds are used in various applications, such as cutting tools, abrasives, and jewelry.
Q84. Which is the largest diamond-producing mine in the world?
a) Aikhal, Russia
b) Argyle, Australia
c) Jwaneng, Botswana
d) Orapa, Botswana
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Correct Answer: a) Aikhal, Russia
Explanation: The Aikhal mine, located in Russia, is the largest diamond-producing mine in the world. The mine is operated by the Russian diamond company ALROSA and has been in operation since 1961. Aikhal produces a significant portion of Russia’s total diamond output, contributing to the country’s position as one of the world’s leading diamond producers.
Q85. Which is the longest animal in the world?
a) Blue whale
b) Giant squid
c) Whale shark
d) Saltwater crocodile
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Correct Answer: a) Blue whale
Explanation: The blue whale is the longest animal in the world, with a recorded length of up to 106 feet (32 meters) and a weight of up to 195 tons (176 metric tons). Blue whales are the largest animals ever known to have lived on Earth, and they inhabit oceans worldwide, feeding primarily on krill.
Q86. Which animal has the longest lifespan?
a) Giant tortoise
b) Bowhead whale
c) Greenland shark
d) Red sea urchin
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Correct Answer: a) Giant tortoise
Explanation: Giant tortoises have the longest lifespan of any animal, with some individuals living for 190 to 200 years. These slow-moving reptiles are native to the Galápagos Islands and the Aldabra Atoll and are known for their large size and longevity.
Q87. Which is the largest land animal?
a) African bush elephant
b) Asian elephant
c) White rhinoceros
d) Hippopotamus
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Correct Answer: a) African bush elephant
Explanation: The African bush elephant is the largest land animal, with adult males weighing up to 12,000 kilograms (26,455 pounds) and standing up to 4 meters (13 feet) tall at the shoulder. These elephants are native to various habitats across Africa, including savannas, forests, and deserts, and are known for their large size, long tusks, and complex social structure.
Q88. Which is the fastest animal in the world?
a) Cheetah
b) Peregrine falcon
c) Pronghorn antelope
d) Sailfish
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Correct Answer: a) Cheetah
Explanation: The cheetah is the fastest animal in the world, capable of reaching speeds of up to 70 miles per hour (112 kilometers per hour) in short bursts while chasing prey. Cheetahs are native to Africa and parts of the Middle East and are known for their slender bodies, long legs, and distinctive black “tear marks” on their faces.
Q89. Which animal can jump the longest distance?
a) Kangaroo
b) Impala
c) Snow leopard
d) Grasshopper
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Correct Answer: a) Kangaroo
Explanation: Kangaroos are known for their incredible jumping abilities, with some species capable of leaping distances of up to 9 meters (30 feet) in a single bound. These marsupials are native to Australia and use their powerful hind legs and large feet to propel themselves through their environment.
Q90. Which bird has the longest wingspan?
a) Sooty albatross
b) Wandering albatross
c) Andean condor
d) Marabou stork
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Correct Answer: b) Wandering albatross
Explanation: The wandering albatross has the longest wingspan of any bird, with some individuals reaching up to 3.7 meters (12 feet) from tip to tip. These large seabirds are found in the Southern Ocean and are known for their incredible ability to glide for long distances over the open ocean, using their large wings to take advantage of wind currents.