DAV Class 4 Science Chapter 1: My Body – Complete Solved Answers
Introduction
The human body is made up of many different organs that work together to keep us healthy and active. Some organs can be seen from outside, while others are present inside our body. In this chapter, students learn about the human body, different types of teeth, the digestive system, healthy eating habits, and the importance of keeping food clean and safe.
Below are the complete and detailed solved answers for DAV Class 4 Science Chapter 1 – My Body.
A. Fill in the Blanks
1. The body organs that cannot be seen from outside are called __________ organs.
Answer: Internal
Internal organs are the organs present inside our body. Examples include the heart, lungs, stomach, liver, and intestines.
2. Flat teeth are in the __________ of the mouth.
Answer: front
Flat teeth are also called incisors. They help us cut and bite food into smaller pieces.
3. The tongue is used for __________ and __________.
Answer: tasting, speaking
The tongue helps us taste different foods. It also helps us speak clearly and move food inside the mouth while chewing.
4. Saliva is secreted by __________.
Answer: Salivary glands
Salivary glands produce saliva. Saliva helps to soften food and begins the process of digestion.
5. Flies can transfer __________ to uncovered food.
Answer: Germs
Flies may carry germs from dirty places to food. Therefore, food should always be kept covered.
B. Match the Following
| Column A | Correct Match | Column B |
|---|---|---|
| Milk teeth | (e) | Twenty |
| Large intestine | (a) | Absorption of water |
| Permanent teeth | (d) | Thirty-two |
| Rectum | (c) | Undigested waste is collected |
| Small intestine | (b) | Absorption of digested food |
C. Tick (✓) the Correct Option
1. The teeth used to tear food into pieces are known as:
(a) Incisors
(b) Canines ✓
(c) Molars
(d) Premolars
Answer: Canines
Canines are pointed teeth that help us tear food into pieces.
2. Ria's mother is thirty-two years old. She is likely to have:
(a) 20 permanent teeth
(b) 20 temporary teeth
(c) 32 permanent teeth ✓
(d) 32 temporary teeth
Answer: 32 permanent teeth
An adult generally has 32 permanent teeth.
3. The organ which secretes digestive juices is the:
(a) Liver ✓
(b) Salivary glands
(c) Stomach
(d) Food pipe
Answer: Liver
The liver produces bile, which helps in the digestion of food.
4. The food gets completely digested in the:
(a) Mouth
(b) Stomach
(c) Small intestine ✓
(d) Large intestine
Answer: Small intestine
Most digestion and absorption of nutrients take place in the small intestine.
5. An eight-year-old child is likely to have:
(a) Only temporary teeth
(b) Only permanent teeth
(c) Both temporary and permanent teeth ✓
(d) No teeth at all
Answer: Both temporary and permanent teeth
At around this age, milk teeth begin to fall out and permanent teeth start appearing.
D. Answer the Following Questions in Brief
1. Name the organ through which food enters the stomach.
Answer: Food enters the stomach through the food pipe.
The food pipe carries swallowed food from the mouth to the stomach.
2. How many sets of teeth are formed during one's lifetime?
Answer: Two sets of teeth are formed during one's lifetime.
The first set is called milk teeth or temporary teeth, and the second set is called permanent teeth.
3. Write any one difference between milk teeth and permanent teeth.
Answer: Milk teeth start appearing when a baby is about six months old, whereas permanent teeth start appearing between six and twelve years of age.
Milk teeth are temporary, while permanent teeth usually remain for the rest of a person's life.
4. What do you mean by the term digestion?
Answer: The conversion of food into simple substances so that it can be absorbed and used by the body is called digestion.
Digestion helps our body get nutrients and energy from the food we eat.
5. What happens to the food when it enters the stomach?
Answer: When food enters the stomach, digestive juices mix with it, and partial digestion takes place.
The stomach churns and mixes the food before passing it to the small intestine.
E. Answer the Following Questions
1. List five good habits that should be taken care of at the time of eating food.
Answer:
- Wash your hands properly before eating food.
- Wash raw fruits and vegetables thoroughly.
- Chew food properly before swallowing.
- Drink plenty of clean water.
- Eat a healthy and balanced diet.
Following these healthy habits helps us remain fit and protects us from diseases.
2. Name the different types of teeth present in the mouth. Also mention their functions.
There are different types of teeth, and each type performs a special function.
| Type of Teeth | Function |
|---|---|
| Flat teeth (Incisors) | Used for cutting and biting food |
| Pointed teeth (Canines) | Used for tearing food |
| Premolars | Used for chewing and crushing food |
| Molars | Used for chewing and grinding food |
Together, all these teeth help us break food into smaller pieces before it enters the digestive system.
3. Why is it important to chew the food properly?
Answer: It is important to chew food properly because chewing breaks food into small pieces. This makes food easier to swallow and helps digestive juices mix properly with it.
Proper chewing also makes the process of digestion easier.
4. Why is washing vegetables and fruits important for us?
Answer: Fruits and vegetables may have dust, dirt, germs, or other harmful substances on their surface. Washing them properly helps remove these impurities.
Therefore, fruits and vegetables should always be washed before eating or cooking to help protect us from stomach problems and illnesses.
5. Sheena's mother often tells her not to eat too many sweets and chocolates. Why do you think she says so?
Answer: Eating too many sweets and chocolates can harm our teeth. Germs in the mouth feed on sugar and may damage the teeth, causing tooth decay.
Therefore, we should limit sugary foods and brush our teeth regularly.
6. Complete the given food path.
The food travels through the digestive system in the following order:
Mouth → Food Pipe → Stomach → Small Intestine → Large Intestine → Rectum → Anus
Explanation of the Food Path
- Mouth: Food is chewed and mixed with saliva.
- Food Pipe: Food travels from the mouth to the stomach.
- Stomach: Food mixes with digestive juices.
- Small Intestine: Food is completely digested, and useful nutrients are absorbed.
- Large Intestine: Water is absorbed from undigested food.
- Rectum: Undigested waste is collected.
- Anus: Waste is removed from the body.
Value-Based Questions
1. What would you do if you were in Rahul's place?
Answer: I would prefer to eat the food offered by Sanyam.
Sharing food with friends is a good habit. We should also make sure that the food is clean and safe to eat.
2. Sanyam tried to share his food with Rahul. In what situations do you share or help your friends?
Answer: I share my food when a friend forgets to bring a lunch box. I also help my friends by sharing useful things such as pencils, sharpeners, erasers, and other school supplies whenever they need them.
Sharing and helping others are good values that strengthen friendship.
3. Do you think eating food from roadside vendors is a healthy option?
Answer: No, eating food from roadside vendors is not always a healthy option because the food may be exposed to dust, dirt, flies, and germs.
We should always try to eat fresh, clean, and properly covered food.
Something to Do
1. Activity: Make a Model of Teeth
Take some playing dough or clay and a few peeled peanuts. Roll the clay into the shape of a jaw and arrange the peanuts like teeth.
Use different colours to show:
- Flat teeth
- Pointed teeth
- Broad and grooved teeth
Answer: Do it yourself.
2. Learn More About the Digestive System
Students can learn more about the human digestive system through educational resources and classroom activities.
Answer: Do it yourself.
Conclusion
The human body is an amazing system in which different organs work together. Teeth help us bite, tear, chew, and grind food, while the digestive system changes food into simple substances that our body can use.
By following healthy eating habits, washing fruits and vegetables, chewing food properly, avoiding too many sweets, and keeping food covered, we can help keep our body healthy and strong.
Quick Revision Points
- Internal organs cannot be seen from outside.
- Humans develop two sets of teeth.
- Milk teeth are temporary teeth.
- Adults generally have 32 permanent teeth.
- Incisors help in cutting and biting.
- Canines help in tearing food.
- Premolars and molars help in chewing and grinding.
- Digestion changes food into simpler substances.
- The small intestine is the main site where digestion is completed and nutrients are absorbed.
- Food should always be clean and properly covered.
- Good eating habits help us stay healthy.
DAV Class 4 Science Chapter 1: My Body is an important chapter that teaches children about their body, teeth, digestion, and healthy habits in a simple and practical way.
