Class 9 Science

Why Do We Fall Ill?

Extra Questions & Answers

Question 1: What do you understand by health?

Answer: It is a state of being well enough to properly function physically, mentally and socially. In other words, health is a state of physical, mental and social well being.

Question 2: How does public cleanliness affect our health?

Answer: Public cleanliness is important for our health. If someone is living in a filthy neighborhood, he has a greater risk of being affected by some or the other epidemic.

Question 3: What do you understand by disease?

Answer: A condition in which the affected person is unable to carry out normal activities is termed as disease.

Question 4: What do you understand by symptoms?

Answer: Apparent signs which give a clue about an underlying disease are called symptoms. For example; headache, fever, abdominal cramps, etc.

Question 5: What is an acute disease?

Answer: A disease which appears for a short duration is called acute disease. In most of the cases, an acute disease does not result in debility. Example: cholera, diarrhea, flu, common cold, etc.

Question 6: What do you understand by non-infectious disease?

Answer: When a disease happens because of some malfunctioning in any organ and it is not because of any microorganism, it is called non-infectious disease. A non-infectious disease may happen because of a wrong lifestyle. Some non-infectious diseases may happen because of genetic factor, i.e. they are right from the birth. Example: diabetes, hypertension, heart disease, arthritis, hemophilia, etc.

Question 7: What is a chronic disease?

Answer: A disease which lasts for many years is called chronic disease. Some of the chronic diseases may last for the entire life. A chronic disease often results in debility. Example: arthritis, tuberculosis, diabetes, hypertension, etc.

Question 8: What is an infectious disease?

Answer: When a disease happens because of a microorganism, it is called infectious disease. Bacteria, protozoa, virus and fungi are the causes of diseases in this case. Example: diarrhea, tuberculosis, dengue, malaria, hepatitis, etc.

Question 9: What is an antibiotic?

Answer: A substance which stops the growth of bacteria or kills the bacteria is called antibiotic. Antibiotic is given to treat or prevent bacterial infection.

Question 10: What are vectors for a disease?

Answer: Some animals work as vehicles to transfer infection from one person to another. Such animals are called vectors.

Question 11: Which animal plays the role of vector for malaria?

Answer: Female Anopheles mosquito

Question 12: Which animal plays the role of vector for rabies?

Answer: Dogs, cats, mongoose, monkey

Question 13: What are the limitations of treating an infection?

Answer: Treating an infection has following limitations:

Question 14: How can we prevent air borne diseases?

Answer: Air borne disease can be prevented by some simple measures. If you are suffering from common cold then you should cover your face while sneezing or coughing. In case of a flu scare in the city, you should wear a face mask while going to a public place or traveling by public transport.

Question 15: How can we prevent water borne diseases?

Answer: Water borne disease can be prevented by avoiding the use of contaminated water. You should always carry drinking water from home. If that is not possible then you should buy bottled water for drinking. Never buy food from those vendors who do not keep their food items covered. Don’t eat stale or spoiled food items.

Question 16: Write a short note on vaccination.

Answer: Vaccination is based on the principle that our body learns to fight against a certain microbe when the microbe attacks our body for the first time. Vaccines are made from dead or weak strains of a microbe. Vaccine is inoculated in the body in appropriate dose. After vaccination, the body learns to fight with that microbe. As a result, our body easily wards off any future onslaught of that microbe. Many diseases can be prevented by vaccines.