(i) The problem is of tooth decay which causes toothache.
(ii) One should clean the teeth with a toothbrush twice a day. Chocolates should be avoided.
(iii) She is aware and concerned about the problems arising in the teeth especially of younger children.

The various components of food are as following:
(i) Carbohydrates
(ii) Fats
(iii) Proteins
(iv) Vitamins
(v)Minerals
(vi) Water and Roughage

Carbohydrates are complex substances. These complex substances cannot be utilised as such as we eat. They are broken down into simpler substances like glucose. This process is called digestion of carbohydrates.

(i) It helps in talking.
(ii) It helps to mix saliva with the food.
(iii)It also helps in swallowing food.

The different organs of the alimentary canal are as follows:
(i) Mouth and mouth cavity
(ii) Oesophagus
(iii) Stomach
(iv) Small intestine
(v) Large intestine
(vi) Anus

Cellulose rich food substances are good source of roughage in human beings. It is because the cellulose digesting bacteria are not present in the body of human beings due to which human beings cannot digest cellulose (present in plant foods).

Yes, liver produces bile which has bile salts. These salts break large fat molecules to fine droplets. These fine droplets are further converted into fatty acids and glycerol.

The process by which nutrients from the digested food are absorbed by the body is called absorption whereas the process by which the absorbed nutrients are utilised by
the body for providing energy is called assimilation.

The swallowed food moves downwards in the alimentary canal because of the alternate relaxation contraction movement of muscles in the wall of foodpipe called peristalsis.

Mucus protects the inner lining of stomach form the action of hydrochloric acid and enzyme pepsin. If mucus is not released, it will lead to erosion of inner lining of stomach leading to acidity and ulcers.

Sometimes when we eat hurriedly, talks or laughs while eating, the flap-like valve (called epiglottis) which closes the passage of windpipe remains open. Therefore, the food may enter into the windpipe. Coughing helps to clear the passage and returns the food particle back to the foodpipe.

The various components of food and their simpler forms are

No, we connot survive only on raw, vegetables/grasses. This is due to the absence of cellulose degrading/digesting enzymes. Raw plants, vegetables and grasses, etc, contain chlorophyll, which is digested in ruminants by the action of microorganism but humans do not posses these microorganisms. Therefore, we would not be able to digest cellulose and meet our energy requirements.