Roughage (dietary fibre) is provided by all plant products like fruits, pulses, vegetables, etc. It acts as food for animals, helps us in getting rid of the undigested food from the body and keeps our skin healthy. 

Wheat, rice, potato and sweet potato are sources of carbohydrates. But rice contains the highest level of starch and is the richest source of carbohydrates.

Food is required by our body for its growth and proper functioning. It also provides us energy. Oxygen is not made from food.

To maintain the nutrient content of the body for optimal growth, one should eat a balanced diet. A balanced diet basically includes 5 major nutrients: proteins, fats, carbohydrates, vitamins and minerals. Also, water and dietary fibres make a part of our diet, but water is not included in nutrients.

The lack or the excess of anything is harmful, e.g. lack of fat lowers the body energy and intake of excess fat results in obesity.

Deficiency of proteins in the diet for a long time results in swelling of the face, swollen neck, undergrowth of the body, etc. This is because proteins are the building blocks of the body and should be taken in sufficient amounts.

A person who does not take proteins and carbohydrates in his diet for long may become so lean and thin that he will not be able to walk properly and his growth may also stop completely. This is because these two are the major nutrients for our body.

Lack of any nutrient in the body causes one or another disease in the body. Scurvy is the disease which is prevented by the intake of citrus fruits like oranges, lemons, etc.

Goitre – Swollen neck glands Scurvy – Bleeding gums Rickets – Bow-shaped legs Beriberi – Weak muscles and laziness 

Vitamins are major components of our food. They strengthen our body to fight against diseases.

Our teeth and bones are basically formed from the compounds of calcium, the deficiency of which leads to their decay.

Dietary fibre or roughage helps in proper digestion and easy bowel movement and thus, aids in removing waste from the body.

Vitamins are the major components of our balanced diet and are taken from outside sources, i.e. these cannot be synthesised by the body itself. Vitamin D is an exception, which is prepared by the body in the presence of sunlight.

Vitamin A helps in keeping our skin and eyes healthy. Carbohydrates and fats are energy providing foods and proteins are basic building blocks of the body.

To test the presence of proteins in any substance, two drops of copper sulphate followed by ten drops of caustic soda are added. If the colour of the solution does not change, it means proteins are absent. If the colour changes from white to violet, it confirms the presence of proteins. Milk, egg and pulses give positive test for proteins. So, the chemicals used are caustic soda and copper sulphate.