Study of factors connected with the improvement of human race ?
Answer: B
Eugenics is the study of improving the human race by controlling who reproduces.
Galton coined the term in 1883. In the twentieth century it was used to justify forced sterilisation and worse, and it is now wholly discredited. Euthenics, by contrast, seeks improvement through better surroundings.
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Which one of the following air pollution can affect blood stream leading to death ?
Answer: B
Carbon monoxide acts on the bloodstream and can kill.
It binds to haemoglobin about 240 times more strongly than oxygen does, forming carboxyhaemoglobin, so the blood can no longer carry oxygen. Being colourless and odourless it gives no warning.
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Damage to hearing is caused by sounds which exceed
Answer: D
Sound above 120 decibels damages hearing at once.
That is the threshold of pain, comparable to a jet engine at close range. Prolonged exposure above 85 dB damages hearing more slowly, which is why 85 dB is the usual occupational limit.
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How many eyes are found in an earthworm?
Answer: C
The earthworm has no eyes.
Living underground it has no use for them. It detects light through photoreceptor cells scattered in the skin, densest at the front end, which is enough to make it retreat from the surface into its burrow.
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Dicotyledonous weeds are destroyed by a chemical called
Answer: B
Dicotyledonous weeds are killed by 2,4-dichlorophenoxyacetic acid, or 2,4-D.
It is a synthetic auxin that throws the plant's growth into disorder. It is selective because monocots - the cereals - metabolise it quickly, so a cereal field can be sprayed to kill the broadleaved weeds in it.
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Plant have ____ while animals lack it.
Answer: B
Plants have cellulose; animals do not.
It is the polymer of glucose that makes up the plant cell wall and gives it rigidity. Animal cells have no wall at all. Starch, protein and fat occur in both kingdoms.
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Pollination by wind is called
Answer: A
Pollination by wind is anemophily, from the Greek anemos, wind.
Wind-pollinated flowers are small, dull and scentless, with exposed anthers, feathery stigmas and enormous quantities of light dry pollen. Grasses, cereals and most trees of the temperate forest are anemophilous.
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Surplus red blood cells, needed to meet an emergency, are MAINLY stored in which organ of the human body?
Answer: B
Surplus red cells are stored mainly in the spleen.
It holds a reserve that contraction of its smooth muscle can release into the circulation during haemorrhage or strenuous exercise. The spleen also filters out worn-out red cells, which is why it is called the graveyard of erythrocytes.
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The plant dye Henna imparts orangered colour to skin and hairs due to its reaction with which of the following?
Answer: A
Henna colours skin and hair by reacting with protein and amino acids.
Its dye, lawsone, binds to the keratin of skin and hair, which is why the colour is fast on those tissues but washes off anything else. The reaction is with the amino groups of the protein.
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Bronchitis is a disease of
Answer: A
Bronchitis is a disease of the respiratory tract - inflammation of the bronchi, the airways leading to the lungs.
The lining swells and produces excess mucus, causing the persistent cough. Acute bronchitis usually follows a viral infection; the chronic form is caused chiefly by smoking.
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