1. Why do living things need food?

All living things need food to survive. Food gives us the energy and nutrients the body needs to maintain health and life, to grow and develop, to move, work, play, think and learn. The body needs a variety of nutrients like proteins, carbohydrates, fats, vitamins and minerals and these come from the foods we eat. Proteins are needed to build and maintain muscle, blood, skin and bones and other tissues and organs in the body. Carbohydrates and fats mainly provide energy. Vitamins and minerals are needed in smaller amounts than protein, fat and carbohydrates, but they are essential for good nutrition. They help the body work properly and stay healthy.

2. What is tasting?

Tasting is the sense that distinguishes the sweet, sour, salty, and bitter qualities of dissolved substances in contact with the taste buds on the tongue.  The tongue uses taste buds or sensor cells to determine the type of food and send taste signals back to our brains.

3. How do we taste our food?

We taste our food with the help of our tongue. The tongue is really made up of many groups of muscles. These muscles run in different directions to carry out all the tongue's jobs. The front part of the tongue is very flexible and can move around a lot, working with the teeth to create different types of words. This part also helps us eat by helping to move food around our mouth while we chew. Our tongue pushes the food to our back teeth so the teeth can grind it up. The back of our tongue is important for eating. Different sides of the tongue get different tastes. We can taste something sweet from the centre and the front of the tongue. We can taste something salty from the front of the tongue. We can taste something bitter from the back of the tongue. We can taste sourness at the sides of the tongue.

4. What are taste buds ? How does it helps in tasting food?

The front, back and the edges of our tongue are covered with small bumps known as taste buds. Taste buds helps us to taste food. Taste buds contain the receptors for taste. They are located around the small structures on the upper surface of the tongue. Taste buds are sensory organs that allows us to experience tastes that are sweet, salty, sour, and bitter. Taste buds have very sensitive microscopic hairs called microvilli. Those tiny hairs send messages to the brain about how something tastes. The average person has about 10,000 taste buds and they're replaced every 2 weeks or so. But as a person ages, some of those taste cells do not get replaced. An older person may only have 5,000 working taste buds. That's why certain foods may taste stronger to us than they do to adults.

5. What is digestion?

Digestion is the process of breaking down of food into simpler substances that can be used by our body. Digestion, allows our body to get the nutrients and energy it needs from the food we eat. Digestion involves mixing food with digestive juices, moving it through the digestive tract, and breaking down large molecules of food into smaller molecules. Digestion begins in the mouth, when we chew and swallow, and is completed in the small intestine.

6. What is the digestive system?

The human digestive system is a complex series of organs and glands that processes food. In order to use the food we eat, our body has to break the food down into smaller molecules that it can process; it also has to excrete waste. The digestive system helps to break the food that we eat into simple forms so that it can be used by the body. The digestive system is made up of the digestive tract, a series of hollow organs joined in a long, twisting tube from the mouth to the anus and other organs that help the body break down and absorb food. Organs that make up the digestive system t are the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus.

7. Explain the digestion process in  human beings.

The digestive system starts in the mouth. The food is broken down into smaller pieces by chewing with the help of our teeth. The food is mixed with a juice called saliva in the mouth, which makes the food wet and make it easy to swallow. Then it goes through the food pipe to the stomach. In the stomach, it mixes with the digestive juices. The food then goes to the small intestine. Here, the useful part of the food is taken in by the blood and sent to different parts of the body. The undigested food passes from the small intestine to the large intestine. From there it is thrown out of the body through the anus.

8. Why is digestion important?

Digestion is necessary to facilitate metabolism of food. The food that we eat contains various nutrients like proteins, vitamins, carbohydrates, minerals etc, that provide energy, immunity, serve as building blocks and nourishes the body. In the food that we eat, nutrients are in the form of large molecules that are physically and chemically bound together. Digestion breaks down this bond of complex molecules into simpler nutrient molecules that can be absorbed by the body to support its day-to-day functions. If food wasn't broken down, it would stay in the body and continue to build up. This could cause severe weight gain. Indigestion of food can also cause health problems.

9. What is glucose?

Glucose is a carbohydrate and is the most important simple sugar in human metabolism. Glucose is called a simple sugar or a monosaccharide because it is one of the smallest units which has the characteristics. Food is absorbed in the blood in the form of glucose.

10. Define nutrients.

Nutrients are substances that rebuilds the body, repair tissues and gives energy. There are many different nutrients. Water, being the most needed nutrients, is good for energy. Carbohydrates, proteins, fats, vitamins and minerals are also a good source for much needed nutrients.