1)What is roughage and explain its function?
Food containing plant fibres, which are also known as dietary fibres, is called roughage. The main function of roughage is to help our body get rid of undigested food.
2)What is a balanced diet? Write the components of a balanced diet.
A diet which provides the right proportion of all the nutrients that our body needs along with roughage and water is called a balanced diet. The various components of a balanced diet are carbohydrates, fats, proteins, vitamins, minerals, roughage and water.
3)Why should a meal have different food items?
 A meal should have different food items because our body needs different kinds of nutrients for proper functioning.
4)What are nutrients? Name the major nutrients.
The components of food which are needed by our body are called nutrients. The major
nutrients are:
(i) Carbohydrates (ii) Fats (iii) Proteins
(iv) Vitamins (v) Minerals
5)How will you test whether a given food item contains starch?
Take a piece of the given food item. Put 2-3 drops of dilute iodine solution on it. lf the colour of the food item becomes blue-black, then it indicates the presence of starch in the food item.
[ i) Food + Iodine - Blue-black colour (starch present)
(ii) Food + lodine - No blue-black colour (no starch present)
6)What are the functions of proteins?
Proteins constitute the most important type of nutrient. Food that contains proteins is called body-building food. lt helps in the growth and repair of damaged cells and tissues of the body. It also helps our body fight against infections. Our nails, hair and muscles are made of proteins.
7)How can you test the presence of proteins in a given food item?
Take a small quantity of the given food item. If the sample is solid, grind it. Put some of this in a clean test tube, add l0 drops of water to it and shake the test tube. Now, with the help of a dropper, add two drops of a solution of copper sulphate and 10 drops of a solution of caustic soda to the test tube. Shake well and let the test tube stand in a test tube stand for a few minutes. Observe the colour of the content. lf the colour of the content turns violet, the food
item contains protein.
Food + water + copper sulphate + caustic soda —> violet colour —> protein is present.
8)What are fats? Name a few substances that contain fats.
Fats are energy-rich nutrients. They provide energy for the body. All types of nuts, mustard seeds, milk and butter are the major sources of fat. Like carbohydrates, fats also contain carbon, hydrogen and oxygen, but fats contain lesser oxygen than carbohydrates.
9)How would you test whether a given food item contains fat?
Take a small quantity of the given food item. Rub it on a piece of white paper. Observe carefully. If you find that the piece of white paper shows an oily patch on it, it indicates that the food item contains fat.
10)What are vitamins? List down the various kinds of vitamins.
Vitamins are protective compounds with no energy value. They help in the proper functioning of the body. They are required by the body in very small quantities.Various kinds of vitamins are Vitamin A, Vitamin B-complex,     Vitamin C, Vitamin D, Vitamin E and Vitamin K.
11)What are the functions of minerals?
Minerals are protective nutrients occurring naturally and are needed by our body in small amounts. Minerals are essential for proper growth of the body.
12)What are deficiency diseases?
Diseases that are caused by the lack of some particular nutrients in a person's diet are called deficiency diseases. When a person eats food which does not contain a particular nutrient continuously for a long time, it leads to the deficiency of that nutrient. This in turn leads into deficiency disease. eg: Scurvy is caused due to the deficiency of Vitamin C.
13)List the various types of nutrients and write the functions of each.
The various nutrients are:
(i) Carbohydrates: They are mainly energy-providing nutrients.
(ii) Fats: They provide energy for the body. They give much more energy than equal amounts of carbohydrates.
(iii) Proteins: They are called body-building nutrients. Proteins help in the formation and repair of body parts. Skin,    hair, muscles, enzymes etc. are made up of proteins.
(iv) Vitamins: Vitamins help in protecting our body against diseases. They also protect eyes, bones, teeth and gums.
(v) Minerals: Minerals are essential for proper growth of the body and to maintain good health.