When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.
What are (i) organisms A, and (ii) substance B?
What are (i) part C, and (ii) part D, of tooth known as?
By what name are the holes E in the tooth known?
Name the part F of the tooth.
What will happen if organisms A reach part F of the tooth known?
Download our app for free and get started
Organism A is bacteria.
Substance B is acid.
Part C is the tooth enamel.
part D is the dentine of the tooth.
The small holes, E, are known as cavities.
F is the pulp of the tooth.
When a bacterium (organism A) reaches the pulp (part F) of the tooth, it irritates the nerve endings and causes toothache.
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
If a person holds his breath after expiration for about 25sec, would there be occurrence of any exchange of respiratory gases in the lungs during this period? Explain.
Some sugar solution is taken in a test-tube and a little of substance X in powder form is added to it. The mouth of test - tube is closed with a cork and allowed to stand for sometime. On opening the cork, a characteristic smell of substance Y is obtained and a gas Z is also observed to be formed. The gas Z extinguishes a burning matchstick.
What could be X, Y and Z?
What is the process of converting sugar into substance Y by the action of X known as?
What type of respiration is exhibited by X in the above process?
An organism X having breathing organs A lives on land. When organism X goes under water, it cannot survive for a long time unless carrying an oxygen cylinder. On the other hand, the organism Y having breathing organs B always lives in water and if taken out of water, it dies after a short while. A third organism Z having breathing organs C and D which lives on the banks of ponds, lakes and rivers can survive on land as well as in water equally well.
What could organism X be? Name the breathing organs A.
What could organism Y be? Name the breathing organs B.
What could organism Z be? Name the breathing organs C and D.