The word 'Denisovan' is sometimes mentioned in media in reference to
- A.fossils of a kind of dinosaurs
- B.an early human species
- C.a cave system found in North-East India
- D.a geological period in the history of Indian subcontinent
Correct answer
Explanation
The correct answer is B, an early human species. Denisovans were an archaic group of humans, close relatives of the Neanderthals, first identified in 2010 from a finger bone found in Denisova Cave in the Altai Mountains of Siberia. They were recognised mainly through ancient DNA rather than through a full skeleton, which made them the first human group defined by its genome. Later finds, such as a jawbone from the Tibetan Plateau, show that they lived across large parts of Asia. Denisovans interbred with modern humans: people in Papua New Guinea, Australia and parts of South-East Asia carry Denisovan DNA, and a gene variant that helps Tibetans live at high altitude came from them. Option A is wrong because Denisovans are humans, not dinosaurs, which died out about 66 million years ago. Option C is wrong because Denisova Cave is in Russia's Altai region, not in North-East India. Option D is wrong because the word does not name a geological period. Exam tip: Denisovans — known from Denisova Cave, Siberia (2010); sister group of the Neanderthals; their genes survive in Melanesians and Tibetans.
Practice Questions
View allA recent movie titled The Man Who Knew Infinity is based on the biography of
- A.S. Ramanujan
- B.S. Chandrasekhar
- C.S. N. Bose
- D.C. V. Raman
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The 2015 film 'The Man Who Knew Infinity' tells the life of the Indian mathematician Srinivasa Ramanujan and is based on Robert Kanigel's 1991 biography of the same name.
Read the full explanation →Which one of the following statements best describes the role of B cells and T cells in the human body?
- A.They protect the body from environmental allergens.
- B.They alleviate the body's pain and inflammation.
- C.They act as immunosuppressants in the body.
- D.They protect the body from the diseases caused by pathogens.
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B cells and T cells are lymphocytes, the white blood cells of the adaptive immune system that recognise and fight specific bacteria, viruses and other pathogens.
Read the full explanation →Which one of the following is not used as fertilizer?
- A.Ammonium nitrate
- B.Ammonium sulphide
- C.Ammonium phosphate
- D.Ammonium sulphate
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Ammonium sulphide is an unstable, foul-smelling compound that breaks down to release ammonia and toxic hydrogen sulphide, so it is not used as a fertiliser.
Read the full explanation →The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eye-piece is
- A.12.5 cm
- B.5 cm
- C.2 cm
- D.10 cm
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For an astronomical telescope in normal adjustment the magnifying power equals the focal length of the objective divided by that of the eyepiece, so the eyepiece focal length is 50 ÷ 25 = 2 cm.
Read the full explanation →The major source of vitamins and minerals for vegetarians is
- A.black gram and wheat.
- B.rice and mustard.
- C.vegetables and fruits.
- D.soya bean and milk.
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Vegetables and fruits supply most of the vitamins and minerals in a vegetarian diet, which is why they are called protective foods.
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