Question
People living in hilly regions usually suffer from simple goitre. Explain.
✓
Answer
Iodine is essential for the production of thyroxin by the thyroid gland. The people living in hilly regions receive insufficient iodine in their diet, due to the fact that they drink iodine deficient water from rivers and streams fed by melting snow. Even their diet has little or no iodine. When there is a deficiency of iodine in the diet the thyroid gland enlarges in order to compensate for this deficiency resulting in goitre.
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(i) From the graph it seems likely that the rate of bubbling per minute at 50 cm would have been
(a) 2.0 (b) 2.5 (c) 3.0 (d) 3.5
(ii) The gas produced by the plant during the experiment was
(a) air (b) oxygen (c) carbon dioxide (d) nitrogen (e) hydrogen
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(a) glucose (b) starch (c) water (d) air (e) ATP
(iv) If ice cubes were added to the water, the rate of bubble formation would
(a) Stay the same.
(b) Increase because more water is added.
(c) Decrease because the temperature drops.
(d) Decrease because water freezes.
(e) Cannot tell from the information given.
(v) If some sodium bicarbonate is added to the water the rate of bubble formation
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(b) Increases because more photosynthesis occurs.
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