1.
Option A
2.
Molars and premolars are used for crushing and grinding food.
3.
Sometimes bits of food remain stuck to the teeth and can cause the growth of bacteria. Bacteria attack the enamel and form a sticky coating called plaque. Then they attack the dentine and finally pulp. When the bacteria reaches the nerves within the pulp, it results in severe pain hence tooth decay is caused.
4.
We must avoid having too many sweets because they spoil our teeth.
5.
We can keep our teeth healthy by brushing early in the morning and before going to sleep and washing mouth after every meal.
6.
Microbes are used in changing milk into curd, produce vitamins in our body, help in decomposition of living organisms, help in digestion of roughage in animals.
7.
Teeth give proper shape to our face. They help us to speak clearly. They enable us to bite and chew food which makes digestion easy.
8.
If we do not brush our teeth regularly they may decay and fall off.
9.
Option B
10.
Option B
11.
We must wash our hands so that the germs stuck to our hands are washed away.
12.
Foods like milk, cheese and cottage cheese are good for our teeth.
13.
Option A
14.
Option B
15.
Fungi are tiny organisms that grow on decaying matter.
16.
Option D
17.
Option B
18.
Option D
19.
Option B
20.
Option A