Diseases and First Aid
Solutions for Biology, Class 8, ICSE
Assertion Reason Type Questions
5 questionsAssertion (A): Infectious diseases are caused due to the entry of pathogens in the body.
Reason (R): Pathogens are usually microorganisms which can easily spread through air, water and food; and get transmitted from an infected person to a healthy person.
- Both A and R are true.
- Both A and R are false.
- A is true and R is false.
- A is false and R is true.
Answer:
Both A and R are true.
Explanation — Infectious diseases spread from an infected person to a healthy person by the entry of microorganisms/ pathogens. They spread through air, water, food, physical contact, cuts, sexual contact and from insects like mosquitoes, flies, etc.
Assertion (A): The disease causing agent/pathogen of 'dengue' is a type of mosquito — Aedes aegypti.
Reason (R): Aedes aegypti spreads germs from a diseased person to a healthy person.
- Both A and R are true.
- Both A and R are false.
- A is true and R is false.
- A is false and R is true.
Answer:
A is false and R is true.
Explanation — Dengue is a mosquito-borne disease caused by the dengue virus. It is spread by a mosquito called Aedes aegypti. Here, the dengue virus is the agent/pathogen, and mosquito Aedes aegypti is the disease causing vector.
Assertion (A): 'HIV' is a kind of fungal disease which is usually transmitted through sexual contact or blood transfusion.
Reason (R): The fungus grows and develops in the reproductive organs of humans and get transmitted easily during sexual contact.
- Both A and R are true.
- Both A and R are false.
- A is true and R is false.
- A is false and R is true.
Answer:
Both A and R are false.
Explanation — HIV is a viral disease, not a fungal disease. It weakens the immune system by attacking WBCs. It is transmitted through sexual contact, blood transfusion, and from mother to child during pregnancy, childbirth, or breastfeeding.
Assertion (A): Garbage should never be kept in covered bins.
Reason: Covered bins provide suitable conditions for the growth and development of germs as well as serve as breeding places for many vectors.
- Both A and R are true.
- Both A and R are false.
- A is true and R is false.
- A is false and R is true.
Answer:
Both A and R are false.
Explanation — Garbage should be kept in covered bins. Covered bins help prevent the growth of germs and restrict breeding of disease-carrying vectors like flies and mosquitoes.
Assertion (A): Diseases like cowpox, smallpox, chickenpox are all caused by the same virus.
Reason (R): The vaccine prepared for smallpox contains the fully virulent, living 'cowpox virus.
- Both A and R are true.
- Both A and R are false.
- A is true and R is false.
- A is false and R is true.
Answer:
A is false and R is true.
Explanation — Diseases like cowpox, smallpox, chickenpox are not caused by the same virus. Cowpox virus and smallpox viruses are similar but not the same. Chickenpox is also caused by a different virus.
Long Answer Questions
4 questionsAnswer:
Vaccination is the practice of artificially introducing germs or germ substances into the body for developing resistance to particular diseases. The material introduced into the body is called the vaccine. Usually, the vaccine is introduced into the body by injection and sometimes orally.
A vaccine can be prepared by any one of the following four methods —
- Using killed germs — e.g. TAB vaccine for typhoid.
- Using living weakened germs — e.g. the vaccine for measles.
- Using fully virulent living germs — e.g. the vaccine for smallpox.
- Using Toxoids — e.g. the vaccines used for diphtheria and tetanus.
Answer:
First aid for burns depends on the degree of burns.
In the case of superficial burns, pour cold water over the burnt area. Then dry that portion and cover with sterile dressing.
In the case of deep burns, never use water, and cover the injured part with dressing.
In the case of chemical burns, wash with running water for 10 minutes and then cover with dressing.
Answer:
(a) Disease — Disease is a departure from normal health through structural or functional disorder of the body. There are two major categories of diseases — Communicable or infectious diseases and Non-Communicable or non-infectious diseases.
(b) Immunization — Immunization is an artificial way of achieving protection from infections by the introduction of dead or weakened germs into one's body. Immunization is a process by which the body of an individual is made resistant to a specific disease by vaccination.
(c) Pathogen — Communicable diseases are caused due to microorganisms such as viruses, bacteria, fungi, worms and protozoa. The disease causing germs are called pathogens. Pathogens spread from one person to other through air, water, food, physical contact, cuts, sexual contact and from insects like mosquitoes, flies, etc.
(d) AIDS — AIDS stands for Acquired Immuno Deficiency Syndrome. It is caused by the HIV virus. It weakens the immunity or self defence mechanism of the human body. AIDS makes the infected person prone to many other infectious diseases. It spreads through sexual contact, blood transfusion and infected syringes.
(e) Vaccination — Vaccination is the practice of artificially introducing germs or germ substances into the body for developing resistance to particular diseases. The material introduced into the body is called the vaccine. When exposed to vaccines, the body makes antibodies and more or less permanent protection from infection is achieved.
(f) Vector — Vectors are those organisms (eg. house flies, mosquitoes, etc.) which carry germs from a source of infection but themselves do not get the infection. For example, mosquitoes while feeding on the blood of a malaria patient, gain the germs in their bodies, and get them transferred in the blood stream of a healthy person whom they bite next.
Given below is a crossword puzzle. Read the clues across and clues downward, and fill up the blank squares. Check up your answers with the correct solution given at the end.
CLUES ACROSS (1-6)
The kind of pathogen which causes diseases like common cold and mumps.
These may readily grow in your hair, if you do not wash it regularly.
This is the vaccine for preventing tuberculosis.
The disease pertussis is popularly known as whooping ...............
One of the most common insects that visit our exposed foods and contaminate them.
A disease that weakens body's defence system against infections.
CLUES DOWN (7-11)
Germ or germ substances introduced into the body to prevent occurrence of an infectious disease.
A disease in which the eyes, the skin and the urine turn yellow.
An organ usually affected by tuberculosis.
A disease caused by the bite of an infected dog, and which affects the central nervous system.
Cover this part of your body by a handkerchief while sneezing to prevent droplet infection to others.

Answer:

CLUES ACROSS (1-6)
VIRUS
LICE
BCG
COUGH
FLIES
AIDS
CLUES DOWN (7-11)
VACCINE
JAUNDICE
LUNG
RABIES
MOUTH
Match The Following
1 questionAnswer:
Column A | Column B |
---|---|
(a) Malaria | (v) Plasmodium |
(b) Chikungunya | (i) Aedes aegypti |
(c) Poliomyelitis | (iv) Salk's vaccine |
(d) Tuberculosis | (ii) BCG |
(e) Typhoid | (iii) TAB |
Name The Following
1 questionAnswer:
(a) AIDS
(b) Malaria
(c) Malaria
(d) Dengue fever, Chikungunya
(e) Tuberculosis
Objective Type Questions
7 questions'Prophylaxis' is a significant concept in medical science to prevent humans from many diseases. Specific vaccines for different diseases are prepared by different methods. Which of the following statements are mismatched?
P. Salk's vaccine for typhoid - using toxoids.
Q. BCG vaccine for tuberculosis - using living weakened germs.
R. Salk's vaccine for poliomyelitis - using killed germs.
- Only P
- Only R
- Only P and Q
- Only Q and R
Answer:
Only P
Reason — The correct match should be:
TAB vaccine for typhoid - using killed germs.
Mohit was playing football in the school playground with his friends. All of a sudden, he fell badly on the ground. His right hand was most likely fractured. What first-aid should be given to him?
- Mohit should be laid down on the ground and the fractured part should be moved continuously.
- Tie a sling to rest the arm on it.
- Apply some alkali, like baking soda on the fractured part.
- Apply hot water bag around the fractured part
Answer:
Tie a sling to rest the arm on it.
Reason — In the given case, Mohit should be laid down comfortably, and the fractured arm should not be moved. We should tie a sling upon which the arm can rest.
Short Answer Questions
19 questionsAnswer:
Four ways of indirect methods by which infectious diseases can spread are:
- Touching and sharing items used by the infected person
- Contaminated food and water or drink
- Vectors
- Droplets
Answer:
First aid is the first and immediate assistance given to any person suffering from either a minor or serious illness or injury, with care provided to preserve life, prevent the condition from worsening, or to promote recovery until full medical treatment is available
Answer:
Non communicable diseases are those which are not caused by any germ, therefore these diseases cannot spread from an infected person to a healthy person (i.e., they are non transmissible). These may be caused due to improper functioning of the body organs. Example : diabetes, heart attack, etc.
Answer:
Communicable diseases are those diseases which spread from an infected person to a healthy person by the entry of microorganisms or pathogens. These diseases are caused by the germs known as pathogens. Example: Chicken pox, Malaria, Typhoid, etc.
Answer:
Public hygiene involves proper disposal of human excreta and domestic wastes. It is equally important as personal hygiene for the following reasons:
- Sewage should be chemically treated first before being released into the water bodies to avoid water-borne diseases. There should be proper sewage lines connected to sewage treatment plants.
- A healthy environment should be maintained by disposing garbage in covered bins to prevent breeding of flies, avoiding stagnation of water to prevent breeding of mosquitoes.
- Contamination of drinking water with faeces (animal or human excreta) should be prevented as it is a major cause of diseases.
Write Full Forms Of The Following
1 questionAnswer:
(a) AIDS - Acquired Immune Deficiency Syndrome
(b) HIV - Human Immunodeficiency Virus
(c) WBCs - White Blood Cells
(d) BCG - Bacillus Calmette-Guerin
(e) TAB - Typhoid-paratyphoid A and B