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Chapter 20 - Man and Biology - Test 4
1.
Decomposers _________ only a small amount of energy.
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2.
An important function performed by _________ is nitrogen fixation.
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3.
Timber is used for making ________.
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4.
Disease and pest resistant varieties have been evolved by ________.
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5.
__________ is the production of silk by the activity of worm known as silk worms.
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6.
Often various diseases of silkworm wipe out ___________.
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7.
Adult silk moth female lays eggs, which _________ in three to four days.
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8.
Domesticating the honeybee for the honey production is known as __________.
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9.
A large number of organism damage useful plants and animals, which are called __________.
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10.
Chemical like ________ are used as insecticide.
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11.
Contamination of the environment with waste products and other impurities is called _____________.
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12.
Substances, whose presence in air, water or soil is harmful to living thing and soil, are termed as __________.
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13.
Sources of water and soil pollution are municipal wastes, industrial wastes and _______ wastes.
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14.
Carbon monoxide combines with _________ to reduce oxygen in blood.
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15.
Untreated sewage is source of germs causing cholera and _______.
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