All questions of Changes Affect Organisms for Grade 3 Exam

Why Sunlight Keeps Rooms Dry and Free from Germs?

Sunlight has the ability to keep rooms dry and free from germs due to its various properties. Let's explore how sunlight helps in achieving this:

UV Rays:
Sunlight contains ultraviolet (UV) rays, specifically UV-C rays, which have the ability to kill germs and bacteria. When sunlight enters a room, it helps in disinfecting surfaces and air, reducing the presence of harmful microorganisms.

Warmth:
Sunlight provides warmth, which helps in drying out damp areas in rooms. Dampness can lead to the growth of mold and mildew, which are not only unsightly but can also pose health risks. By drying out the rooms, sunlight prevents the growth of these harmful substances.

Natural Ventilation:
When sunlight enters a room, it often comes along with fresh air. This natural ventilation helps in circulating air, reducing humidity, and preventing the buildup of moisture. This, in turn, helps in keeping the rooms dry and free from germs.

Psychological Benefits:
In addition to its practical benefits, sunlight also has psychological benefits. Sunlight can improve mood, increase productivity, and create a sense of well-being. A dry and well-lit room can have a positive impact on mental health and overall well-being.

In conclusion, sunlight plays a crucial role in keeping rooms dry and free from germs by its ability to kill bacteria, dry out damp areas, provide natural ventilation, and improve psychological well-being.

Introduction:
Taking care of our teeth is essential for maintaining good oral hygiene and preventing dental problems. There are several important practices that contribute to proper dental care. In this case, we will discuss the options given and explain why option 'A' is not true for the care of teeth.

Explanation:
Option 'A' states that we should not chew the food. However, this statement is not correct when it comes to dental care. Chewing food is an important part of the digestive process and has several benefits for our teeth.

Chewing aids digestion:
- Chewing food thoroughly helps break it down into smaller pieces, making it easier for our stomach to digest.
- The saliva produced during chewing contains enzymes that start the digestion process and help in breaking down carbohydrates.

Stimulates saliva production:
- Chewing stimulates the salivary glands to produce saliva, which helps in neutralizing acids produced by oral bacteria.
- Saliva also contains minerals like calcium and phosphate that help in remineralizing tooth enamel and preventing tooth decay.

Cleans teeth naturally:
- Chewing certain foods, like crunchy fruits and vegetables, acts as a natural toothbrush by removing food particles and plaque from the teeth.
- The fibrous texture of these foods also stimulates the gums, promoting good gum health.

Conclusion:
In conclusion, option 'A' is not true for the care of teeth. Chewing food is an essential part of the digestive process and has several benefits for our teeth, including aiding digestion, stimulating saliva production, and naturally cleaning the teeth. Therefore, it is important to chew food thoroughly as part of maintaining good oral hygiene.

How Flies Spread Diarrhoea:
- Flies often come into contact with feces, sewage, and other sources of harmful bacteria.
- When flies land on food or surfaces, they can transfer these bacteria, leading to contamination.
- Consuming contaminated food or touching contaminated surfaces and then touching one's mouth can result in diarrhoea.

Preventing Diarrhoea Spread by Flies:
- Keep food covered to prevent flies from landing on it.
- Maintain good hygiene practices such as washing hands before eating.
- Dispose of waste properly to reduce fly breeding grounds.
In conclusion, flies play a significant role in spreading diarrhoea by transferring harmful bacteria from contaminated sources to food and surfaces. By implementing proper hygiene practices and preventive measures, the spread of diarrhoea through flies can be minimized.

Key Factors for a Good House

Introduction:
A good house is essential for a comfortable and healthy living environment. There are several factors that contribute to a good house, including cleanliness, ventilation, and maintenance. In this response, we will discuss why frequent cleaning with phenyl is an important aspect of maintaining a good house.

1. Cleanliness:
Cleanliness is a crucial factor when it comes to maintaining a good house. A clean house not only looks aesthetically pleasing but also promotes good health. Regular cleaning helps to remove dust, dirt, and allergens that can accumulate over time. It also prevents the growth of bacteria, mold, and pests, which can cause various health issues.

2. Importance of Frequent Cleaning:
Frequent cleaning is necessary to ensure a clean and hygienic living space. Cleaning with phenyl, a disinfectant, helps to eliminate germs and bacteria effectively. It is especially important in high-traffic areas like kitchens and bathrooms, where the chances of contamination are higher.

3. Benefits of Using Phenyl:
Phenyl is a commonly used cleaning agent that offers several benefits for maintaining a good house:

- Disinfection: Phenyl has disinfectant properties that can kill a wide range of harmful bacteria, viruses, and fungi. This helps in preventing the spread of diseases and infections within the house.

- Odor Control: Phenyl also helps in eliminating unpleasant odors. It leaves behind a fresh and clean scent, making the house more inviting.

- Stain Removal: Phenyl is effective in removing stubborn stains and marks from surfaces. It can be used on various surfaces like floors, tiles, and countertops to keep them clean and spotless.

- Pest Control: Phenyl can act as a deterrent for pests like ants, cockroaches, and flies. Regular cleaning with phenyl can help in keeping these pests at bay, ensuring a pest-free environment.

Conclusion:
In conclusion, a good house should be clean and well-maintained. Frequent cleaning with phenyl is an important aspect of maintaining a good house as it helps in disinfection, odor control, stain removal, and pest control. By prioritizing cleanliness and using appropriate cleaning agents, we can create a healthy and comfortable living space for ourselves and our families.