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Life Processes — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceLife Processes5 Marks
Question
If the teeth are not cleaned regularly, they become covered with a sticky yellowish layer W of food particles and bacteria. Since layer W covers the teeth, the alkaline liquid X secreted by glands Y inside the mouth cannot reach the teeth surface to neutralise the acid formed by the action of organisms Z on sugary food, and hence tooth decay sets in.
  1. What is W known as?
  2. What is (i) X, and (ii) Y?
  3. What are organisms Z?
  4. State one way of removing layer W from the teeth.
✓

Answer

  1. W is the dental plaque.
  2.  
  1. X refers to the saliva.
  2. Y refers to the salivary glands.
  1. Organisms Z are bacteria.
  2. Layer of W, i.e. dental plaque, can be removed by regular brushing of teeth.

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